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 Rev: 072707
DS26900 JTAG Multiplexer/Switch
General Description
The DS26900 is a JTAG signal multiplexer providing connectivity between one of three master ports and up to 18 (36 in cascade configuration) secondary ports. The device is fully configurable from any one of the three master ports. The DS26900 can automatically detect the presence JTAG devices on the secondary ports. The DS26900 can be used in multiple configurations including as a single device, two cascaded devices, or two redundant devices. All device control and configuration is accomplished through standard JTAG operations via the selected master port.
Features
Efficient Solution for Star Architecture JTAG Provides Transparent Communications Between the Arbitrated Master and a Selected Secondary Port Single-Package Solution Provides 18 Secondary Ports Two-Package Cascade Configuration Provides 36 Secondary Ports Three Arbitrated Master Ports Autodetection of Port Presence Internal Pullup/Down Resistors Two 32-Bit Scratchpad Registers Four GPIO Pins for Read/Write Control and Signaling Applications Operation Up to 50MHz Signal Path Modification Options Redundancy with High-Impedance Pin Independent Periphery JTAG Configuration Mode Uses IEEE 1149.1 TAP Controller Supports Live Insertion/Withdrawal 3.3V Operation Industrial Temperature Operation RoHS-Compliant Packaging

Applications
MicroTCA Chassis ATCA Chassis AMC Carrier Cards JSM Modules System Level JTAG

MicroTCA JSM Functional Diagram
AMC1 AMC2
DS26900 JTAG SWITCH
MCH1
MASTER3
MCH2
MASTER2
AMC3 AMC4 AMCn AMC18
PART DS26900N+
Ordering Information
TEMP RANGE -40C to +85C PIN-PACKAGE 144 LQFP
CRAFT
MASTER1
+Denotes a lead-free package.
_____________________________________________
Maxim Integrated Products 1
Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device may be simultaneously available through various sales channels. For information about device errata, go to: www.maxim-ic.com/errata. For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
__________________________________________________________________________________________DS26900
Table of Contents
1. 2. 3. 4. 4.1 BLOCK DIAGRAM ........................................................................................................................... 6 PIN DESCRIPTIONS ........................................................................................................................ 7 FUNCTIONAL DESCRIPTION .......................................................................................................19 DETAILED DESCRIPTION ............................................................................................................ 20 MODES OF OPERATION..................................................................................................................20
Single-Package Mode .......................................................................................................................... 20 Cascade Configuration Modes............................................................................................................. 21 Deselect Mode and Redundancy......................................................................................................... 22 Missing Test Master or Unused Test Master Port ............................................................................... 24 Detection of the Presence of Secondary Ports.................................................................................... 24 Selection of the Secondary Port .......................................................................................................... 24 Master Port/Secondary Port Path Timing Description ......................................................................... 24 4.1.1 4.1.2 4.1.3
4.2
MASTER ARBITRATION...................................................................................................................23
4.2.1 4.2.2 4.2.3 4.2.4
4.3 4.4 4.5 4.6 4.7 5. 5.1 5.2 6. 6.1 7. 8. 8.1 8.2 8.3 8.4 9. 9.1 9.2 9.3
GPIO PINS--GENERAL-PURPOSE I/O ...........................................................................................25 PROGRAMMABLE PULLUP/PULLDOWN RESISTORS..........................................................................25 SIGNAL PATH CONFIGURATION--INVERSIONS ................................................................................25 SWITCH CONFIGURATION BY EXTERNAL TEST MASTER...................................................................25 SWITCH CONFIGURATION BY TEST MASTER 1 OR TEST MASTER 2 ..................................................26 RESETS ......................................................................................................................................... 27 GLOBAL RESET USAGE..................................................................................................................27 SECONDARY PORT RESETS ...........................................................................................................27 CONFIGURATION MODE.............................................................................................................. 28 SWITCH TAP CONTROLLER ...........................................................................................................28
Switch Instructions ............................................................................................................................... 28
6.1.1
DEVICE REGISTERS..................................................................................................................... 31 ADDITIONAL APPLICATION INFORMATION ..............................................................................37 ACCESSING INDIVIDUAL DEVICE JTAG ON A BOARD .......................................................................37 USING LED INDICATORS ON THE SSPI, ACT AND MCI PINS............................................................37 USING 2.7V AND 1.8V LOGIC LEVELS WITH THE DS26900 .............................................................37 SERIES TERMINATION RESISTORS..................................................................................................37 PERIPHERY JTAG ........................................................................................................................ 38 PERIPHERY JTAG DESCRIPTION....................................................................................................38 JTAG TAP CONTROLLER STATE MACHINE DESCRIPTION...............................................................39 JTAG INSTRUCTION REGISTER AND INSTRUCTIONS........................................................................41
SAMPLE/PRELOAD ............................................................................................................................ 41 EXTEST ............................................................................................................................................... 41 BYPASS............................................................................................................................................... 41 IDCODE ............................................................................................................................................... 41 HIGHZ .................................................................................................................................................. 41 CLAMP................................................................................................................................................. 42 Bypass Register ................................................................................................................................... 42 Identification Register........................................................................................................................... 42 Boundary Scan Register ...................................................................................................................... 42
9.3.1 9.3.2 9.3.3 9.3.4 9.3.5 9.3.6
9.4
JTAG TEST REGISTERS ................................................................................................................42
9.4.1 9.4.2 9.4.3
2
__________________________________________________________________________________________DS26900
10.
OPERATING PARAMETERS ........................................................................................................43 THERMAL INFORMATION .............................................................................................................43 DC CHARACTERISTICS...............................................................................................................43 SWITCH TAP CONTROLLER INTERFACE TIMING...........................................................................44 TRANSPARENT MODE MASTER/SLAVE PORT TIMING ...................................................................45 PERIPHERY JTAG INTERFACE TIMING ........................................................................................46
10.1 10.2 11. 11.1 11.2 11.3 12. 13. 14.
AC TIMING ..................................................................................................................................... 44
PIN CONFIGURATION .................................................................................................................. 47 PACKAGE INFORMATION ...........................................................................................................48 144-PIN LQFP (56-G6037-001) ................................................................................................48 DOCUMENT REVISION HISTORY ................................................................................................50
13.1
3
__________________________________________________________________________________________DS26900
List of Figures
Figure 1-1. DS26900 Block Diagram ........................................................................................................................... 6 Figure 4-1. Configuration for 3 Masters, 18 Secondary Ports ................................................................................... 20 Figure 4-2. Configuration for 1 Master, 20 Secondary Ports..................................................................................... 20 Figure 4-3. Two Cascaded Devices........................................................................................................................... 21 Figure 4-4. Three Cascaded Devices Using External Select Logic........................................................................... 22 Figure 9-1. Periphery JTAG Block Diagram .............................................................................................................. 38 Figure 9-2. JTAG TAP Controller State Machine ...................................................................................................... 39 Figure 11-1. Switch TAP Controller Interface Timing Diagram ................................................................................. 44 Figure 11-2. Transparent Mode Master/Slave Port Timing Diagram......................................................................... 45 Figure 11-3. Periphery JTAG Interface Timing Diagram ........................................................................................... 46
4
__________________________________________________________________________________________DS26900
List of Tables
Table 2-1. Pin Descriptions (Sorted by Function)........................................................................................................ 7 Table 2-2. Pin Description (Sorted by Pin Number) .................................................................................................. 13 Table 4-1. Mode Pins................................................................................................................................................. 20 Table 4-2. Master Arbitration ..................................................................................................................................... 23 Table 4-3. ACT Output States.................................................................................................................................... 24 Table 6-1. Switch TAP Instruction Codes.................................................................................................................. 28 Table 7-1. DS26900 List of Registers........................................................................................................................ 31 Table 7-2. Secondary Port Selection Bits and Indicator Pins.................................................................................... 35 Table 9-1. Periphery JTAG Instruction Codes........................................................................................................... 41 Table 10-1. Thermal Characteristics.......................................................................................................................... 43 Table 10-2. Recommended DC Operating Conditions .............................................................................................. 43 Table 10-3. DC Electrical Characteristics.................................................................................................................. 43 Table 11-1. Switch TAP Controller Interface Timing ................................................................................................. 44 Table 11-2. Master/Slave Port Timing ....................................................................................................................... 45 Table 11-3. Periphery JTAG Interface Timing ........................................................................................................... 46
5
__________________________________________________________________________________________DS26900
1. Block Diagram
Figure 1-1. DS26900 Block Diagram
DS26900
5 EXTERNAL TEST PORT TEST MASTER PORT 1 TEST MASTER PORT 2 6 PROG INVERSIONS 6 PORT MUX 5 5 5
SECONDARY 1 SECONDARY 2 SECONDARY 3 SECONDARY 4
6
MGNT MCI MODE [1:0] 5
MASTER ARBITER
SWITCH TAP CONTROLLER
5 SWITCH LOGIC
SECONDARY 18
ACT GPIO [3:0] SSPI [4:0]
REGISTER BANK PERIPHERY TAP CONTROLLER
JTAG
6
__________________________________________________________________________________________DS26900
2. Pin Descriptions Table 2-1. Pin Descriptions (Sorted by Function)
NAME ETCK PIN 4 TYPE Ipd FUNCTION External Test Master Clock. In configuration mode, a falling edge on this pin clocks data in on the ETDI pin. A falling edge on this pin clocks data out on the ETDO pin. When PREN = VDD, a 20k pulldown resistor is connected to this pin. ETDI 2 Ipd External Test Master Serial Data Input. In configuration mode, data is clocked in on this pin on the falling edge of ETCK. When PREN = VDD, a 20k pulldown resistor is connected to this pin. ETDO 3 O/ High Impedance External Test Master Serial Data Out. (High Impedance) Data is clocked out on this pin on the falling edge of ETCK. When PREN = VDD, a 10k pullup resistor is connected to this pin. External Test Master Configuration (Active Low). Asserting this pin low along with EREQ asserted low allows the External Test Master to configure the DS26900, allowing access to the Switch TAP Controller. Toggling ECFG when EREQ is high has no effect. When PREN = VDD, a 10k pullup resistor is connected to this pin. ETMS 6 Ipu External Test Master Test Mode Select. This pin is sampled on the rising edge of ETCK and is used to place the port into the various defined IEEE 1149.1 states. When PREN = VDD, a 10k pullup resistor is connected to this pin. EREQ MGNT0 1 Ipu External Test Master Request (Active Low). (Internal 10k Pullup) When active, this pin selects the external test port as the master. When switching EREQ, none of the master clocks should be toggling. Master Grant 0 (Active Low). Asserted low when the external test master is the arbitrated master. Test Master 1 Test Port Clock TCK1 22 Ipd/O Master Mode = Input Slave Mode = Output When PREN = VDD, an internal 20k pulldown resistor is connected to this pin. Test Master 1 Test Port Serial Data Input TDI1 20 Ipu/O Master Mode = Input Slave Mode = Output When PREN = VDD, an internal 10k pullup resistor is connected to this pin. Test Master 1 Test Port Serial Data Out TDO1 21 I/O Master Mode = Output Slave Mode = Input When PREN = VDD, an internal 10k pullup resistor is connected to this pin. Test Master 1 Test Port Test Reset (Active Low). Asserting this pin low (when master) puts the DS26900 into configuration mode, allowing access to the Switch TAP Controller. Toggling TRST1 when not the arbitrated master has no effect. This pin does not directly affect secondary port resets. Master Mode = TRST1 Input Slave Mode = TRST1 Output When PREN = VDD, an internal 10k pullup resistor is connected to this pin.
ECFG
5
Ipu
144
O
TRST1
23
Ipu/O
7
__________________________________________________________________________________________DS26900
NAME PIN TYPE Master Mode = Input Slave Mode = Output When PREN = VDD, an internal 20k pulldown resistor is connected to this pin. TMREQ1 MGNT1 19 Ipu Test Master 1 Master Request (Active Low). (Internal 10k Pullup) When EREQ is inactive and TMREQ1 is active, this pin selects the test master port 1 as the master. When switching TMREQ1, none of the master clocks should be toggling. Master Grant 1 (Active Low). Asserted low when Test Master 1 is the arbitrated master. Test Master 2 Test Port Clock TCK2 30 Ipd/O Master Mode = Input Slave Mode = Output When PREN = VDD, an internal 20k pulldown resistor is connected to this pin. Test Master 2 Test Port Serial Data Input TDI2 28 Ipu/O Master Mode = Input Slave Mode = Output When PREN = VDD, an internal 10k pullup resistor is connected to this pin. Test Master 2 Test Port Serial Data Out TDO2 29 I/O Master Mode = Output Slave Mode = Input When PREN = VDD, an internal 10k pullup resistor is connected to this pin. Test Master 2 Test Port Test Reset (Active Low). Asserting this pin low (when master) puts the DS26900 into configuration mode, allowing access to the Switch TAP Controller. Toggling TRST2 when not the arbitrated master has no effect. This pin does not directly affect secondary port resets. Master Mode = TRST2 Input Slave Mode = TRST2 Output When PREN = VDD, an internal 10k pullup resistor is connected to this pin. Test Master 2 Test Port Test Mode Select TMS2 32 Ipd/O Master Mode = Input Slave Mode = Output When PREN = VDD, an internal 20k pulldown resistor is connected to this pin. TMREQ2 Test Master 2 Master Request (Active Low) (Internal 10k Pullup) When EREQ and TMREQ1 are inactive and TMREQ2 is active, this pin selects the test master port 2 as the master. When switching TMREQ2, none of the master clocks should be toggling. Master Grant 2 (Active Low). Asserted low when Test Master 2 is the arbitrated master. Secondary Port 1 Test Clock Secondary Port 1 Serial Data In Secondary Port 1 Serial Data Out (Internal 10k Pullup) Secondary Port 1 Test Reset (Active Low) Secondary Port 1 Test Mode Select (Internal 20k Pulldown) Secondary Port 2 Test Clock Secondary Port 2 Serial Data Input Secondary port 2 Serial Data Out (Internal 10k Pullup) Secondary Port 2 Test Reset (Active Low) FUNCTION Test Master 1 Test Port Test Mode Select TMS1 24 Ipd/O
18
O
TRST2
31
Ipu/O
27
Ipu
MGNT2 STCK1 STDI1 STDO1 STRST1 STMS1 STCK2 STDI2 STDO2 STRST2
25 91 92 93 90 89 86 87 88 85
O O O Ipu O O O O Ipu O
8
__________________________________________________________________________________________DS26900
NAME STMS2 STCK3 STDI3 STDO3 STRST3 STMS3 STCK4 STDI4 STDO4 STRST4 STMS4 STCK5 STDI5 STDO5 STRST5 STMS5 STCK6 STDI6 STDO6 STRST6 STMS6 STCK7 STDI7 STDO7 STRST7 STMS7 STCK8 STDI8 STDO8 STRST8 STMS8 STCK9 STDI9 STDO9 STRST9 STMS9 STCK10 STDI10 STDO10 STRST10 STMS10 PIN 84 80 81 82 79 78 75 76 77 74 73 70 71 72 69 68 65 66 67 64 63 59 60 61 58 57 54 55 56 53 52 49 50 51 47 46 43 44 45 42 41 TYPE O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O FUNCTION Secondary Port 2 Test Mode Select (Internal 20k Pulldown) Secondary Port 3 Test Clock Secondary Port 3 Serial Data Input Secondary Port 3 Serial Data Out (Internal 10k Pullup) Secondary Port 3 Test Reset (Active Low) Secondary Port 3 Test Mode Select (Internal 20k Pulldown) Secondary Port 4 Test Clock Secondary Port 4 Serial Data Input Secondary Port 4 Serial Data Out (Internal 10k Pullup) Secondary Port 4 Test Reset (Active Low) Secondary Port 4 Test Mode Select (Internal 20k Pulldown) Secondary Port 5 Test Clock Secondary Port 5 Serial Data Input Secondary Port 5 Serial Data Out (Internal 10k Pullup) Secondary Port 5 Test Reset (Active Low) Secondary Port 5 Test Mode Select (Internal 20k Pulldown) Secondary Port 6 Test Clock Secondary Port 6 Serial Data Input Secondary Port 6 Serial Data Out (Internal 10k Pullup) Secondary Port 6 Test Reset (Active Low) Secondary Port 6 Test Mode Select (Internal 20k Pulldown) Secondary Port 7 Test Clock Secondary Port 7 Serial Data Input Secondary Port 7 Serial Data Out (Internal 10k Pullup) Secondary Port 7 Test Reset (Active Low) Secondary Port 7 Test Mode Select (Internal 20k Pulldown) Secondary Port 8 Test Clock Secondary Port 8 Serial Data Input Secondary Port 8 Serial Data Out (Internal 10k Pullup) Secondary Port 8 Test Reset (Active Low) Secondary Port 8 Test Mode Select (Internal 20k Pulldown) Secondary Port 9 Test Clock Secondary Port 9 Serial Data Input Secondary Port 9 Serial Data Out (Internal 10k Pullup) Secondary Port 9 Test Reset (Active Low) Secondary Port 9 Test Mode Select (Internal 20k Pulldown) Secondary Port 10 Test Clock Secondary Port 10 Serial Data Input Secondary Port 10 Serial Data Out (Internal 10k Pullup) Secondary Port 10 Test Reset (Active Low) Secondary Port 10 Test Mode Select (Internal 20k Pulldown)
9
__________________________________________________________________________________________DS26900
NAME STCK11 STDI11 STDO11 STRST11 STMS11 STCK12 STDI12 STDO12 STRST12 STMS12 STCK13 STDI13 STDO13 STRST13 STMS13 STCK14 STDI14 STDO14 STRST14 STMS14 STCK15 STDI15 STDO15 STRST15 STMS15 STCK16 STDI16 STDO16 STRST16 STMS16 STCK17 STDI17 STDO17 STRST17 STMS17 STCK18 STDI18 STDO18 STRST18 STMS18 N.C. PIN 138 139 140 137 136 132 134 135 131 130 127 128 129 126 125 122 123 124 121 120 116 117 118 115 114 111 112 113 110 109 105 106 107 104 103 100 101 102 99 98 94, 95 TYPE O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O -- Secondary Port 11 Test Clock Secondary Port 11 Serial Data Input Secondary Port 11 Serial Data Out (internal 10k pullup) Secondary Port 11 Test Reset (Active Low) Secondary Port 11 Test Mode Select (Internal 20k Pulldown) Secondary Port 12 Test Clock Secondary Port 12 Serial Data Input Secondary Port 12 Serial Data Out (Internal 10k Pullup) Secondary Port 12 Test Reset (Active Low) Secondary Port 12 Test Mode Select (Internal 20k Pulldown) Secondary Port 13 Test Clock Secondary Port 13 Serial Data Input Secondary Port 13 Serial Data Out (Internal 10k Pullup) Secondary Port 13 Test Reset (Active Low) Secondary Port 13 Test Mode Select (Internal 20k Pulldown) Secondary Port 14 Test Clock Secondary Port 14 Serial Data Input Secondary Port 14 Serial Data Out (Internal 10k Pullup) Secondary Port 14 Test Reset (Active Low) Secondary Port 14 Test Mode Select (Internal 20k Pulldown) Secondary Port 15 Test Clock Secondary Port 15 Serial Data Input Secondary Port 15 Serial Data Out (Internal 10k Pullup) Secondary Port 15 Test Reset (Active Low) Secondary Port 15 Test Mode Select (Internal 20k Pulldown) Secondary Port 16 Test Clock Secondary Port 16 Serial Data Input Secondary Port 16 Serial Data Out (internal 10k pullup) Secondary Port 16 Test Reset (Active Low) Secondary Port 16 Test Mode Select (Internal 20k Pulldown) Secondary Port 17 Test Clock Secondary Port 17 Serial Data Input Secondary Port 17 Serial Data Out (Internal 10k Pullup) Secondary Port 17 Test Reset (Active Low) Secondary Port 17 Test Mode Select (Internal 20k Pulldown) Secondary Port 18 Test Clock Secondary Port 18 Serial Data Input Secondary Port 18 Serial Data Out (Internal 10k Pullup) Secondary Port 18 Test Reset (Active Low) Secondary Port 18 Test Mode Select (Internal 20k Pulldown) No Connection FUNCTION
10
__________________________________________________________________________________________DS26900
NAME SSPI4 PIN 8 TYPE O FUNCTION Selected Secondary Port Indicator Bit 4 (Active Low). Along with pins SSPI3, SSPI2, SSPI1, and SSPI0, this pin provides a hardware indication of the selected secondary port. See Table 7-2 for more information. Selected Secondary Port Indicator Bit 3 (Active Low). Along with pins SSPI4, SSPI2, SSPI1, and SSPI0, this pin provides a hardware indication of the selected secondary port. See Table 7-2 for more information. Selected Secondary Port Indicator Bit 2 (Active Low). Along with pins SSPI4, SSPI3, SSPI1, and SSPI0, this provides a hardware indication of the selected secondary port. See Table 7-2 for more information. Selected Secondary Port Indicator Bit 1 (Active Low). Along with pins SSPI4, SSPI3, SSPI2, and SSPI0, this pin provides a hardware indication of the selected secondary port. See Table 7-2 for more information. Selected Secondary Port Indicator Bit 0 (Active Low). Along with pins SSPI4, SSPI3, SSPI2, and SSPI1, this pin provides a hardware indication of the selected secondary port. See Table 7-2 for more information. General-Purpose Input/Output Bit 3. (Internal 20k Pulldown) This pin is a generalpurpose input/output, which can be read or driven via a register bit. This pin is in input mode after a global reset. General-Purpose Input/Output Bit 2. (Internal 20k Pulldown) This pin is a generalpurpose input/output, which can be read or driven via a register bit. This pin is in input mode after a global reset. General-Purpose Input/Output Bit 1. (Internal 20k Pulldown) This pin is a generalpurpose input/output, which can be read or driven via a register bit. This pin is in input mode after a global reset. General-Purpose Input/Output Bit 0. (Internal 20k Pulldown) This pin is a generalpurpose input/output, which can be read or driven via a register bit. This pin is in input mode after a global reset. Global Reset (Active Low). (Internal 10k Pullup) A low state on this pin provides an asynchronous reset for global registers and logic. RST should be tied high for normal operation. Test Enable (Active Low). (Internal 10k Pullup) Factory test input. TEST must be tied high or unconnected for normal operation. Output High-Impedance Enable (Active Low). When this pin is asserted low, internal pullup and pulldown resistors are disabled, all outputs are put into highimpedance mode, and master request inputs (EREQ, TMREQ1, TMREQ2) are disabled. PTRST must also be asserted logic 0. Mode Select Bit 1. (Internal 20k Pulldown) Selects mode of operation of the device (Single-Package, Cascade-Master, Cascade-Extension, or Deselect. Mode Select Bit 0. (Internal 20k Pulldown) Selects mode of operation of the device (Single-Package, Cascade-Master, Cascade-Extension, or Deselect). Master Conflict Indicator (Active Low). Indicates that more than one device is requesting to be master. Asserted low when more than one of the EREQ, TMREQ1, or TMREQ2 signals is asserted low. Deselected Port Data Value. This pin directly indicates the state of the DPDV bit in the Device Configuration Register (DCR). Periphery JTAG Chain Test Clock. This input must be driven to a logic level during normal operation. Periphery JTAG Chain Serial Data Input. This input must be driven to a logic level during normal operation. Periphery JTAG Chain Serial Data Out
SSPI3
9
O
SSPI2
10
O
SSPI1
11
O
SSPI0
12
O
GPIO[3]
14
Ipd/O
GPIO[2]
15
Ipd/O
GPIO[1]
16
Ipd/O
GPIO[0]
17
Ipd/O
RST TEST
33
Ipu
62
Ipu
HIZ
143
I
M[1] M[0]
141 142
Ipd Ipd
MCI
34
O
DPDV PTCK PTDI PTDO
96 40 39 38
O I I O
11
__________________________________________________________________________________________DS26900
NAME PTRST PTMS PIN 37 35 TYPE I Ipu FUNCTION Periphery JTAG Chain Test Reset (Active Low). During normal operation, this signal is asserted low. Periphery JTAG Chain Test Mode Select. This input must be driven to a logic level during normal operation. Active (Active Low). Indicates that this device is active when low. An active device is determined by the MSB of the instruction code and the state of the mode pins M0 and M1. Pull-Resistor Enable. When connected to VDD, the following pull resistors are enabled: PREN 7 I 20k pulldown on TCK1, TCK2, ETDI, ETCK, TMS1, TMS2 10k pullup on TDI1, TDI2, ETDO, TDO1, TDO2, TRST1, TRST2, ECFG, ETMS When connected to VSS, the pull resistors on the signals above are disabled. When multiple devices are connected in parallel only one device should have PREN connected = VDD. VDD VSS 13, 36, 83, 119 26, 48, 108, 133 P Positive Supply. 3.3V 5%. All VDD signals should be tied together. Ground Reference. All VSS signals should be tied together.
ACT
97
O
P
Configuration Mode. The master is communicating with the Switch TAP Controller in the DS26900. Transparent Mode. The master is communicating directly with the selected secondary port. All pins are I/O in periphery JTAG mode except the TEST, TMREQ1, TMREQ2, EREQ, M1, M0, HIZ, RST, PTRST, PTCK, PTDI, PTDO, and PTMS pins. All outputs are rated at 8mA. Unused inputs must be tied to logic 1 or 0 if not used and a pullup/pulldown is not present. O = Output I = Input Ipu = Input with an internal pullup Ipd = Input with an internal pulldown P = Power
12
__________________________________________________________________________________________DS26900
Table 2-2. Pin Description (Sorted by Pin Number)
NAME EREQ PIN 1 TYPE Ipu FUNCTION External Test Master Request (Active Low). (Internal 10k Pullup) When active, this pin selects the external test port as the master. When switching EREQ, none of the master clocks should be toggling. External Test Master Serial Data Input. In configuration mode, data is clocked in on this pin on the falling edge of ETCK. When PREN = VDD, a 20k pulldown resistor is connected to this pin. ETDO 3 O/ High Impedance External Test Master Serial Data Out. (High Impedance) Data is clocked out on this pin on the falling edge of ETCK. When PREN = VDD, a 10k pullup resistor is connected to this pin. External Test Master Clock. In configuration mode, a falling edge on this pin clocks data in on the ETDI pin. A falling edge on this pin clocks data out on the ETDO pin. When PREN = VDD, a 20k pulldown resistor is connected to this pin. External Test Master Configuration (Active Low). Asserting this pin low along with EREQ asserted low allows the External Test Master to configure the DS26900, allowing access to the Switch TAP Controller. Toggling ECFG when EREQ is high has no effect. When PREN = VDD, a 10k pullup resistor is connected to this pin. ETMS 6 Ipu External Test Master Test Mode Select. This pin is sampled on the rising edge of ETCK and is used to place the port into the various defined IEEE 1149.1 states. When PREN = VDD, a 10k pullup resistor is connected to this pin. Pull-Resistor Enable. When connected to VDD, the following pull resistors are enabled: PREN 7 I 20k pulldown on TCK1, TCK2, ETDI, ETCK, TMS1, TMS2 10k pullup on TDI1, TDI2, ETDO, TDO1, TDO2, TRST1, TRST2, ECFG, ETMS When connected to VSS, the pull resistors on the signals above are disabled. When multiple devices are connected in parallel only one device should have PREN connected = VDD. SSPI4 8 O Selected Secondary Port Indicator Bit 4 (Active Low). Along with pins SSPI3, SSPI2, SSPI1 and SSPI0, provides a hardware indication of the selected secondary port. See Table 7-2 for more information. Selected Secondary Port Indicator Bit 3 (Active Low). Along with pins SSPI4, SSPI2, SSPI1 and SSPI0, provides a hardware indication of the selected secondary port. See Table 7-2 for more information. Selected Secondary Port Indicator Bit 2 (Active Low). Along with pins SSPI4, SSPI3, SSPI1 and SSPI0, provides a hardware indication of the selected secondary port. See Table 7-2 for more information. Selected Secondary Port Indicator Bit 1 (Active Low). Along with pins SSPI4, SSPI3, SSPI2 and SSPI0, provides a hardware indication of the selected secondary port. See Table 7-2 for more information. Selected Secondary Port Indicator Bit 0 (Active Low). Along with pins SSPI4, SSPI3, SSPI2 and SSPI1, provides a hardware indication of the selected secondary port. See Table 7-2 for more information. Positive Supply. 3.3V 5%. All VDD signals should be tied together. General-Purpose Input/Output Bit 3. (Internal 20k Pulldown) This pin is a generalpurpose input/output, which can be read or driven via a register bit. This pin is in input mode after a global reset.
ETDI
2
Ipd
ETCK
4
Ipd
ECFG
5
Ipu
SSPI3
9
O
SSPI2
10
O
SSPI1
11
O
SSPI0
12 13, 36, 83, 119 14
O P Ipd/O
VDD GPIO[3]
13
__________________________________________________________________________________________DS26900
NAME GPIO[2] PIN 15 TYPE Ipd/O FUNCTION General-Purpose Input/Output Bit 2. (Internal 20k Pulldown) This pin is a generalpurpose input/output, which can be read or driven via a register bit. This pin is in input mode after a global reset. General-Purpose Input/Output Bit 1. (Internal 20k Pulldown) This pin is a generalpurpose input/output, which can be read or driven via a register bit. This pin is in input mode after a global reset. General-Purpose Input/Output Bit 0. (Internal 20k Pulldown) This pin is a generalpurpose input/output, which can be read or driven via a register bit. This pin is in input mode after a global reset. Master Grant 1 (Active Low). Asserted low when Test Master 1 is the arbitrated master. Test Master 1 Master Request (Active Low). (Internal 10k Pullup) When EREQ is inactive and TMREQ1 is active, this pin selects the test master port 1 as the master. When switching TMREQ1, none of the master clocks should be toggling. Test Master 1 Test Port Serial Data Input TDI1 20 Ipu/O Master Mode = Input Slave Mode = Output When PREN = VDD, an internal 10k pullup resistor is connected to this pin. Test Master 1 Test Port Serial Data Out TDO1 21 I/O Master Mode = Output Slave Mode = Input When PREN = VDD, an internal 10k pullup resistor is connected to this pin. Test Master 1 Test Port Clock TCK1 22 Ipd/O Master Mode = Input Slave Mode = Output When PREN = VDD, an internal 20k pulldown resistor is connected to this pin. Test Master 1 Test Port Test Reset (Active Low). Asserting this pin low (when master) puts the DS26900 into configuration mode, allowing access to the Switch TAP Controller. Toggling TRST1 when not the arbitrated master has no effect. This pin does not directly affect secondary port resets. Master Mode = TRST1 Input Slave Mode = TRST1 Output When PREN = VDD, an internal 10k pullup resistor is connected to this pin. Test Master 1 Test Port Test Mode Select TMS1 24 Ipd/O Master Mode = Input Slave Mode = Output When PREN = VDD, an internal 20k pulldown resistor is connected to this pin. MGNT2 VSS 25 26, 48, 108, 133 O P Master Grant 2 (Active Low). Asserted low when Test Master 2 is the arbitrated master. Ground Reference. All VSS signals should be tied together. Test Master 2 Master Request (Active Low). (Internal 10k Pullup) When EREQ and TMREQ1 are inactive and TMREQ2 is active, this pin selects the test master port 2 as the master. When switching TMREQ2, none of the master clocks should be toggling. Test Master 2 Test Port Serial Data Input TDI2 28 Ipu/O Master Mode = Input Slave Mode = Output When PREN = VDD, an internal 10k pullup resistor is connected to this pin.
GPIO[1]
16
Ipd/O
GPIO[0] MGNT1 TMREQ1
17 18
Ipd/O O
19
Ipu
TRST1
23
Ipu / O
TMREQ2
27
Ipu
14
__________________________________________________________________________________________DS26900
NAME PIN TYPE Master Mode = Output Slave Mode = Input When PREN = VDD, an internal 10k pullup resistor is connected to this pin. Test Master 2 Test Port Clock TCK2 30 Ipd/O Master Mode = Input Slave Mode = Output When PREN = VDD, an internal 20k pulldown resistor is connected to this pin. Test Master 2 Test Port Test Reset (Active Low). Asserting this pin low (when master) puts the DS26900 into configuration mode, allowing access to the Switch TAP Controller. Toggling TRST2 when not the arbitrated master has no effect. This pin does not directly affect secondary port resets. Master Mode = TRST2 Input Slave Mode = TRST2 Output When PREN = VDD, an internal 10k pullup resistor is connected to this pin. Test Master 2 Test Port Test Mode Select TMS2 32 Ipd/O Master Mode = Input Slave Mode = Output When PREN = VDD, an internal 20k pulldown resistor is connected to this pin. RST 33 Ipu Global Reset (Active Low). (Internal 10k Pullup) A low state on this pin provides an asynchronous reset for global registers and logic. RST should be tied high for normal operation. Master Conflict Indicator (Active Low). Indicates that more than one device is requesting to be master. Asserted low when more than one of the EREQ, TMREQ1, or TMREQ2 signals is asserted low. Periphery JTAG Chain Test Mode Select. This input must be driven to a logic level during normal operation. Periphery JTAG Chain Test Reset (Active Low). During normal operation, this signal is asserted low. Periphery JTAG Chain Serial Data Out Periphery JTAG Chain Serial Data Input. This input must be driven to a logic level during normal operation. Periphery JTAG Chain Test Clock. This input must be driven to a logic level during normal operation. Secondary Port 10 Test Mode Select (Internal 20k Pulldown) Secondary Port 10 Test Reset (Active Low) Secondary Port 10 Test Clock Secondary Port 10 Serial Data Input Secondary Port 10 Serial Data Out (Internal 10k Pullup) Secondary Port 9 Test Mode Select (Internal 20k Pulldown) Secondary Port 9 Test Reset (Active Low) Secondary Port 9 Test Clock Secondary Port 9 Serial Data Input Secondary Port 9 Serial Data Out (Internal 10k Pullup) Secondary Port 8 Test Mode Select (Internal 20k Pulldown) Secondary Port 8 Test Reset (Active Low) FUNCTION Test Master 2 Test Port Serial Data Out TDO2 29 I/O
TRST2
31
Ipu/O
MCI
34
O
PTMS PTRST PTDO PTDI PTCK STMS10 STRST10 STCK10 STDI10 STDO10 STMS9 STRST9 STCK9 STDI9 STDO9 STMS8 STRST8
35 37 38 39 40 41 42 43 44 45 46 47 49 50 51 52 53
Ipu I O I I O O O O Ipu O O O O Ipu O O
15
__________________________________________________________________________________________DS26900
NAME STCK8 STDI8 STDO8 STMS7 STRST7 STCK7 STDI7 STDO7 TEST STMS6 STRST6 STCK6 STDI6 STDO6 STMS5 STRST5 STCK5 STDI5 STDO5 STMS4 STRST4 STCK4 STDI4 STDO4 STMS3 STRST3 STCK3 STDI3 STDO3 STMS2 STRST2 STCK2 STDI2 STDO2 STMS1 STRST1 STCK1 STDI1 STDO1 N.C. DPDV PIN 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 84 85 86 87 88 89 90 91 92 93 94, 95 96 TYPE O O Ipu O O O O Ipu Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu -- O Secondary Port 8 Test Clock Secondary Port 8 Serial Data Input Secondary Port 8 Serial Data Out (Internal 10k Pullup) Secondary Port 7 Test Mode Select (Internal 20k Pulldown) Secondary Port 7 Test Reset (Active Low) Secondary Port 7 Test Clock Secondary Port 7 Serial Data Input Secondary Port 7 Serial Data Out (Internal 10k Pullup) Test Enable (Active Low). (Internal 10k Pullup) Factory test input. TEST must be tied high or unconnected for normal operation. Secondary Port 6 Test Mode Select (Internal 20k Pulldown) Secondary Port 6 Test Reset (Active Low) Secondary Port 6 Test Clock Secondary Port 6 Serial Data Input Secondary Port 6 Serial Data Out (Internal 10k Pullup) Secondary Port 5 Test Mode Select (Internal 20k Pulldown) Secondary Port 5 Test Reset (Active Low) Secondary Port 5 Test Clock Secondary Port 5 Serial Data Input Secondary Port 5 Serial Data Out (Internal 10k Pullup) Secondary Port 4 Test Mode Select (Internal 20k Pulldown) Secondary Port 4 Test Reset (Active Low) Secondary Port 4 Test Clock Secondary Port 4 Serial Data Input Secondary Port 4 Serial Data Out (Internal 10k Pullup) Secondary Port 3 Test Mode Select (Internal 20k Pulldown) Secondary Port 3 Test Reset (Active Low) Secondary Port 3 Test Clock Secondary Port 3 Serial Data Input Secondary Port 3 Serial Data Out (Internal 10k Pullup) Secondary Port 2 Test Mode Select (Internal 20k Pulldown) Secondary Port 2 Test Reset (Active Low) Secondary Port 2 Test Clock Secondary Port 2 Serial Data Input Secondary port 2 Serial Data Out (Internal 10k Pullup) Secondary Port 1 Test Mode Select (Internal 20k Pulldown) Secondary Port 1 Test Reset (Active Low) Secondary Port 1 Test Clock Secondary Port 1 Serial Data In Secondary Port 1 Serial Data Out (Internal 10k Pullup) No Connection Deselected Port Data Value. This pin directly indicates the state of the DPDV bit in the Device Configuration Register (DCR). FUNCTION
16
__________________________________________________________________________________________DS26900
NAME ACT STMS18 STRST18 STCK18 STDI18 STDO18 STMS17 STRST17 STCK17 STDI17 STDO17 STMS16 STRST16 STCK16 STDI16 STDO16 STMS15 STRST15 STCK15 STDI15 STDO15 STMS14 STRST14 STCK14 STDI14 STDO14 STMS13 STRST13 STCK13 STDI13 STDO13 STMS12 STRST12 STCK12 STDI12 STDO12 STMS11 STRST11 STCK11 STDI11 STDO11 PIN 97 98 99 100 101 102 103 104 105 106 107 109 110 111 112 113 114 115 116 117 118 120 121 122 123 124 125 126 127 128 129 130 131 132 134 135 136 137 138 139 140 TYPE O O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu O O O O Ipu FUNCTION Active (Active Low). Indicates that this device is active when low. An active device is determined by the MSB of the instruction code and the state of the M0, M1 mode pins. Secondary Port 18 Test Mode Select (Internal 20k Pulldown) Secondary Port 18 Test Reset Secondary Port 18 Test Clock Secondary Port 18 Serial Data Input Secondary Port 18 Serial Data Out (Internal 10k Pullup) Secondary Port 17 Test Mode Select (Internal 20k Pulldown) Secondary Port 17 Test Reset (Active Low) Secondary Port 17 Test Clock Secondary Port 17 Serial Data Input Secondary Port 17 Serial Data Out (Internal 10k Pullup) Secondary Port 16 Test Mode Select (Internal 20k Pulldown) Secondary Port 16 Test Reset (Active Low) Secondary Port 16 Test Clock Secondary Port 16 Serial Data Input Secondary Port 16 Serial Data Out (Internal 10k Pullup) Secondary Port 15 Test Mode Select (Internal 20k Pulldown) Secondary Port 15 Test Reset (Active Low) Secondary Port 15 Test Clock Secondary Port 15 Serial Data Input Secondary Port 15 Serial Data Out (Internal 10k Pullup) Secondary Port 14 Test Mode Select (Internal 20k Pulldown) Secondary Port 14 Test Reset (Active Low) Secondary Port 14 Test Clock Secondary Port 14 Serial Data Input Secondary Port 14 Serial Data Out (Internal 10k Pullup) Secondary Port 13 Test Mode Select (Internal 20k Pulldown) Secondary Port 13 Test Reset (Active Low) Secondary Port 13 Test Clock Secondary Port 13 Serial Data Input Secondary Port 13 Serial Data Out (Internal 10k Pullup) Secondary Port 12 Test Mode Select (Internal 20k Pulldown) Secondary Port 12 Test Reset (Active Low) Secondary Port 12 Test Clock Secondary Port 12 Serial Data Input Secondary Port 12 Serial Data Out (Internal 10k Pullup) Secondary Port 11 Test Mode Select (Internal 20k Pulldown) Secondary Port 11 Test Reset (Active Low) Secondary Port 11 Test Clock Secondary Port 11 Serial Data Input Secondary Port 11 Serial Data Out (Internal 10k Pullup)
17
__________________________________________________________________________________________DS26900
NAME M[1] M[0] PIN 141 142 TYPE Ipd Ipd FUNCTION Mode Select Bit 1. (Internal 20k Pulldown) Selects mode of operation of the device (Single-Package, Cascade-Master, Cascade-Extension, or Deselect). Mode Select Bit 0. (Internal 20k Pulldown) Selects mode of operation of the device (Single-Package, Cascade-Master, Cascade-Extension, or Deselect). Output High-Impedance Enable (Active Low). When this pin is asserted low, internal pullup and pulldown resistors are disabled, all outputs are put into high impedance mode, and master request inputs (EREQ, TMREQ1, TMREQ2) are disabled. PTRST must also be asserted logic 0. Master Grant 0 (Active Low). Asserted low when the External Test Master is the arbitrated master.
HIZ
143
I
MGNT0
144
O
Configuration Mode. The master is communicating with the Switch TAP Controller in the DS26900. Transparent Mode. The master is communicating directly with the selected secondary port. All pins are I/O in periphery JTAG mode except the TEST, TMREQ1, TMREQ2, EREQ, M1, M0, HIZ, RST, PTRST, PTCK, PTDI, PTDO, and PTMS pins. All outputs are rated at 8mA. Unused inputs must be tied to logic 1 or 0 if not used and a pullup/pulldown is not present. O = Output I = Input Ipu = Input with an internal pullup Ipd = Input with an internal pulldown P = Power
18
__________________________________________________________________________________________DS26900
3. Functional Description
The DS26900 is a star (radial) configuration system-level JTAG signal multiplexer, which provides connectivity between a master port and secondary ports. The master port, which has been granted control of the switch, can also treat the unselected master ports as secondary ports. There are three possible master ports: ETM (External Test Master), TM1 (Test Master 1), and TM2 (Test Master 2). ETM functions as the primary master with TM1 and TM2 available as alternative masters. Direct arbitration determines which of the three possible masters can control the switch. ETM has the highest priority whenever there is a conflict over which master port can control the device. See Section 4.2 for more information on master port arbitration. JTAG connectivity is provided for up to 18 secondary ports per package as well as two additional secondary ports, TM1 and TM2, when they are not functioning as a master. Two DS26900s can be cascaded to provide additional secondary ports. The DS26900 can be in one of four modes: Single-Package Mode, Cascade-Master Mode, Cascade-Extension Mode, and Deselect Mode. The DS26900 contains two TAP controllers: one as part of the primary switch function and one to control the traditional JTAG interface at the periphery of the device for manufacturing test purposes. Configuration of the DS26900 is accomplished via the Switch TAP Controller. Configuration options include sensing the presence of secondary ports, addressing the target secondary port, reading/writing scratchpad registers, GPIO pin read/write, generating port resets, configuring path and signaling inversion options, and placing the DS26900 in transparent mode for direct communications with the secondary port. Communications with the DS26900 is accomplished via a master port while asserting the associated ports configure signal (TRST1, TRST2, or ECFG) low. Connected ports (cards) are detected by sensing the port's TMS pullup resistor, and the results are available in the Port Detection Register (PDR). Selection of the desired port is accomplished by setting the address in the Secondary Port Selection Register (SPSR). Once the destination port selection bits are written, the Switch TAP Controller is returned to idle/reset state and the configuration signal (TRST) is asserted high. The DS26900 routes the JTAG signal set (clock, data-in, data-out, mode select, and reset) from the arbitrated master to the selected destination port with controlled timing relationships. A reset for the secondary port can be generated by writing a register bit after a port address is selected. Test masters can be swapped without affecting the logic state of the selected secondary port. The DS26900 also contains traditional boundary scan circuitry at the periphery of the package for board manufacturing tests. See Section 9. This periphery boundary scan circuitry is independent and has priority over the operation of the master/slave multiplexer. It contains a separate TAP controller with a 3-bit wide instruction code register. Signals associated with the periphery boundary scan circuitry are PTRST, PTMS, PTCK, PTDI, and PTDO. The DS26900 switch is designed to work at clock rates up to 50MHz. The arbitrated master is the source of the operating clock. However, the separate periphery JTAG function, as described above, operates at a maximum frequency of 10MHz.
19
__________________________________________________________________________________________DS26900
4. Detailed Description
4.1 Modes of Operation
The mode pins, M1 and M0, provide four modes of operation as described in Table 4-1.
Table 4-1. Mode Pins
M1 0 0 1 1 M0 0 1 0 1 MODE OF OPERATION Single-Package Cascade-Master Cascade-Extension Deselect DESCRIPTION 18 secondary ports, TM1 and TM2 slave ports when configuration bit TM_SLAVE set to logic 1. First group of 18 secondary ports, TM1 and TM2 are slave ports. Second group of 18 secondary ports. Device is deselected (acts as if no master is present).
4.1.1 Single-Package Mode Single-Package Mode allows access to 18 or 20 secondary ports. See Table 4-1 for M0 and M1 pin settings. If the TM_SLAVE bit in the DCR register is set = 0, the device is configured for three master ports and 18 secondary ports, as shown in Figure 4-1. If the TM_SLAVE bit in the DCR register is set = 1, the device is configured for one master port and 20 secondary ports, as shown in Figure 4-2.. In this configuration, TM1 and TM2 are used as secondary ports 19 and 20. If one or more master ports are unused, their REQ input pin(s) must be connected = VDD and the remaining unused inputs must be connected = VDD or VSS, but cannot be left floating. Figure 4-1. Configuration for 3 Masters, 18 Secondary Ports
VDD EXTERNAL TEST MASTER TEST MASTER 1
6
PREN SECONDARY 1 ETM
6
5
DS26900
M[1:0] = 00
5
TM1
6
SECONDARY 18 TM2 INSTRUCTION CODE = "0xxxx"
TEST MASTER 2
Figure 4-2. Configuration for 1 Master, 20 Secondary Ports
VDD EXTERNAL TEST MASTER
6
PREN ETM
5
SECONDARY 1
DS26900
M[1:0] = 00
5
SECONDARY 18 SECONDARY 19 SECONDARY 20
5 5
INSTRUCTION CODE = "0xxxx" SCR.TM_SLAVE = 1
20
__________________________________________________________________________________________DS26900 4.1.2 Cascade Configuration Modes The cascade configuration allows two devices to be connected together, the cascade master and the cascade extension device. This provides access to 36 secondary ports plus the TM1 and TM2 ports (as slave ports) of the extension device without external control logic. The cascade master has its mode pins (M[1:0]) set = 01 and the cascade extension has its mode pins (M[1:0]) set = 10. See Table 4-1 for M0 and M1 pin settings. In Figure 4-3, secondary ports 1 to 18 or 19 to 36 are selected by the MSB of the instruction code. Each device has a 5-bit instruction register. The lower four LSBs have common definitions between the cascade devices, but the MSB of the 5-bit instruction register acts as an address bit. Instructions to be executed by the cascade master have their MSB set to 0. Instructions to be executed by the cascade extension have their MSB set to 1. The same instructions are loaded into each device, but only the appropriate device (determined by the mode pin setting) executes the instruction. The PREN pin on the cascade master is connected = VDD to enable internal pullup/down resistors. On the cascade extension device, PREN is connected = VSS to disable internal pullup/down resistors. If one or more master ports are unused, their REQ input pin(s) must be connected = VDD and the remaining unused inputs must be connected = VDD or VSS, but cannot be left floating. Figure 4-3. Two Cascaded Devices
VDD EXTERNAL TEST MASTER TEST MASTER 1
6
PREN SECONDARY 1 ETM
6
5
DS26900
M[1:0] = 01 (MASTER)
5
TM1
6
SECONDARY 18 TM2 INSTRUCTION CODE = "0xxxx"
TEST MASTER 2
PREN SECONDARY 19 ETM
5
DS26900
M[1:0] = 10 (EXTENSION)
5
TM1
SECONDARY 36 TM2 INSTRUCTION CODE = "1xxxx"
21
__________________________________________________________________________________________DS26900 4.1.3 Deselect Mode and Redundancy Deselect Mode allows multiple devices to be connected in parallel with the use of external logic controlling the M[1:0] and PREN pins. Deselect Mode is enabled when the mode pins (M[1:0]) are both set high. This internally forces the TMREQ1, TMREQ2, and EREQ signals to go high, causing the DS26900 to act as though no active master is present. When both mode pins are set low via the external select logic, the device is selected and operated in Single-Package Mode. Applications requiring device redundancy can be achieved by asserting PTRST low and HIZ low. This causes outputs to become high impedance and disables the pullups and pulldowns. During normal operation, PTRST is asserted low and HIZ is asserted high. A device that is deselected (M[1:0] = 11) internally acts as if an arbitrated master is not present. The Switch TAP Controller goes into Test-Logic-Reset (and the instruction register is cleared). The other programmable registers are left unchanged. Figure 4-4. Three Cascaded Devices Using External Select Logic
VDD EXTERNAL TEST MASTER TEST MASTER 1 TEST MASTER 2
6
PREN ETM
6
5
SECONDARY 1
TM1
6
DS26900
5
TM2
SECONDARY 18 INSTRUCTION CODE = "0xxxx"
M[1:0] = 00/11
PREN ETM TM1 MODE SELECT LOGIC TM2 SECONDARY 1
5
DS26900
5
SECONDARY 18 INSTRUCTION CODE = "0xxxx"
M[1:0] = 00/11
PREN ETM TM1 TM2 SECONDARY 1
5
DS26900
5
SECONDARY 18 INSTRUCTION CODE = "0xxxx"
M[1:0] = 00/11
22
__________________________________________________________________________________________DS26900
4.2
Master Arbitration
The DS26900 can have one of three possible master ports: External Test Master (ETM), Test Master 1 (TM1), or Test Master 2 (TM2). The TM1 and TM2 ports can be bidirectional based on the state of the configuration bit TM_SLAVE. An application, which has less than three masters, can use any combination of master ports. Table 4-2 lists the possible signal configurations and arbitrations for master. In the table, BLOCKED indicates that the JTAG signals are ignored both to and from this port, SLAVE indicates that this port is a target for the JTAG master, MASTER indicates the JTAG signal source port, CONFIG indicates the configuration mode for the DS26900, and NORMAL indicates normal JTAG signal operation from master to slave.
Table 4-2. Master Arbitration
EREQ L L L L L H H H H H ECFG L H H H H X X X X X TMREQ1 L L L H H L L H H H TRST1 X X X X X L H X X X TMREQ2 L L H L H L L L L H TRST2 X X X X X X X L H X ACTIVE MASTER ETM ETM ETM ETM ETM TM1 TM1 TM2 TM2 NONE MODE CONFIG NORMAL NORMAL NORMAL NORMAL CONFIG NORMAL CONFIG NORMAL INACTIVE TM1 INTERFACE MODE BLOCKED BLOCKED BLOCKED SLAVE SLAVE MASTER MASTER SLAVE SLAVE SLAVE TM2 INTERFACE MODE BLOCKED BLOCKED SLAVE BLOCKED SLAVE BLOCKED BLOCKED MASTER MASTER SLAVE
Note: Slave mode of TM1 and TM2 is affected by the state of the configuration bit TM_SLAVE. L = Connect = VSS; H = Connect = VDD; X = Don't care
Only one master is allowed at any time. A test master that is in slave mode has the sense of all the JTAG signals reversed (outputs become inputs, inputs become outputs, and only TMREQ does not change), and it functions identically to a secondary port. A test master that is blocked has its control signals ignored (the JTAG outputs are blocked, JTAG inputs are set to a constant logic level, TMREQ is unaffected). Since the TM ports lack a separate configuration signal, TRST functions as the configuration signal. To avoid glitches on the output secondary ports, all the master signals (TMS, TDI, TDO, and CLK) should be set to logic 0 while switching the master to/from Test Master 1 or Test Master 2. The TM1/TM2 slave interface mode will additionally be affected by the state of the configuration bit TM_SLAVE. If an active master is not present (EREQ, TMREQ1, and TMREQ2 are all logic 1), the Switch TAP Controller goes into Test-Logic-Reset and the content of the instruction register is cleared. All other registers retain their values. The MSB of the last instruction, before clearing, is always retained in a separate register unless global reset is asserted. The port whose address is in the Secondary Port Selection Register (SPSR) is technically still selected, and that port will not be affected by the state of the DPDV bit in the Device Configuration Register (DCR). If a different master becomes the active master, communications can resume with the port whose address is in the Secondary Port Selection Register and whose instruction register MSB is of the proper value. The Secondary Port Selection Register should be written with all zeros once communications with secondary ports is completed. A DS26900 in Deselect Mode disables detection of EREQ, TMREQ1, and TMREQ2, and the device therefore acts as if an active master is not present. Deselect Mode is selected when the mode pins (M[1:0]) are both asserted high.
23
__________________________________________________________________________________________DS26900 The master grant signals, MGNT0, MGNT1, and MGNT2, are generated by the master arbitrator. These signals are available to the appropriate master to indicate that it has control. The MCI output is asserted low to indicate this possible conflict should more than one of the REQ signals be asserted low. An active signal indicates the active (selected) device by asserting ACT low. The ACT pin is asserted low under the conditions listed in Table 4-3.
Table 4-3. ACT Output States
M1 PIN 0 0 0 0 1 1 1 X
X = Don't care
M0 PIN 0 0 1 1 0 0 1 X
INSTRUCTION REGISTER VALUE 0XXXX 1XXXX 0XXXX 1XXXX 0XXXX 1XXXX XXXXX XXXXX
IS THERE AN ACTIVE MASTER? Yes Yes Yes Yes Yes Yes X No
ACT OUTPUT 0 1 0 1 1 0 1 1
4.2.1 Missing Test Master or Unused Test Master Port An unused or missing test master has its TMREQ signal tied high by the user (DS26900 has a pullup on that input pin so the user can leave this pin unconnected), which puts that port into slave mode. 4.2.2 Detection of the Presence of Secondary Ports The presence of secondary ports is detected by sensing the logic level present on the STMSn signal (the STMSn signal on a port should have a pullup) on each secondary port and test master port. Logic 1 is latched into the 20-bit Port Detection Register (PDR) for each pullup that is sensed. The STMSn and TMSn signals are sensed and the Port Detection Register (PDR) is updated each time the Switch TAP Controller passes out of the reset state. (TMSn signals can only be sensed on TM1/TM2 slave-mode ports.) 4.2.3 Selection of the Secondary Port Selection of the secondary port ("slave") is accomplished by writing a 5-bit address into the Secondary Port Selection Register (SPSR). Due to the star configuration, only one port can be selected at a time. Ports that are not detected as being present by sensing the pullup on the secondary port's TMS pin can still be selected, and the signals will be sent to that port. This 5-bit secondary port selection address is complemented and used to generate the selected slave port indicator bits (SSPI[4:0]). These bits can be used as a visual indicator as to which slave port has been selected. Once communications with a secondary port has been completed, the Secondary Port Selection Register (SPSR) should be set to all zeros. If not, the selected port address will not respond to the DPDV bit of the Device Configuration Register (DCR). This is true if an active master is present or not. 4.2.4 Master Port/Secondary Port Path Timing Description Each of the arbitrated masters passes into a 3 x 1 multiplexer and then a 1 x 20 multiplexer, such that any of the three possible masters can connect to any of the 20 possible secondary ports (18 secondary ports plus the test master ports when available). The test clock (TCK), test mode select (TMS), test data in (TDI), and test data out 24
__________________________________________________________________________________________DS26900 (TDO) signals can each be individually inverted by setting an optional configuration bit. Figure 1-1 diagrams this path in a simple form.
4.3
GPIO Pins--General-Purpose I/O
The general-purpose I/O (GPIO) are bidirectional pins that offer the user the ability to output logic levels or read input logic levels. Each GPIO pin can be configured to output logic 1, logic 0, or to be an input. Configuration of the GPIO pins for write or read operation is accomplished by writing the GPIO Configuration and Write Register (GPIOCR) bits. The reading the logic state of the GPIO pins can be accomplished by accessing the 4-bit GPIO Read Register (GPIORR). Pins that are configured for read mode read the input logic state in the register. Pins that are configured for output mode read back the logic state for which those pins are configured.
4.4
Programmable Pullup/Pulldown Resistors
A hardware configuration pin (PREN) is provided to enable/disable pull resistors on the input signal pins of the three masters. PREN works such that when connected to VDD, the following signals have pull resistors enabled: TCK1, TCK2, ETDI, ETCK, TMS1, TMS2--20k pulldown TDI1, TDI2, ETDO, TDO1, TDO2--10k pullup TRST1, TRST2, ECFG, ETMS--10k pullup When connected to VSS, the pull resistors on the signals above are disabled. PREN can be connected to VDD for single device implementations or for one of the devices in a multiple-device implementation. Connecting PREN to VDD on multiple devices, which are in parallel, would cause the pull resistors to be connected in parallel. This would have the undesirable effect of halving the pull-resistor values.
4.5
Signal Path Configuration--Inversions
To help overcome possible timing issues, the JTAG signal path timing can be modified in limited ways in the Device Configuration Register (DCR). Signal path timing changes are global and, once set, they apply to all secondary ports until reconfigured. Figure 1-1 diagrams the relative placement of the signal path modifier logic. There are several possible options: * * * * The test clock (TCK) from the arbitrated master to a slave port can be inverted by setting the TCKi bit. The test data from the arbitrated master to a slave port can be inverted by setting the TDIi bit. The test data coming from the slave port to the arbitrated master can be inverted by setting the TDOi bit. The TMS signal from the arbitrated master to a slave port can be inverted by setting the TMSi bit.
There is only one set of configuration bits. Switching from port to port does not change the configuration bits.
4.6
Switch Configuration by External Test Master
The External Test Master (ETM) has the highest priority in the master arbitration circuit, so asserting EREQ low makes the ETM the master. The ETM accesses the configuration mode of the switch by asserting EREQ low and ECFG low. Access is then provided to the Switch TAP Controller. While in configuration mode, the secondary slave ports' JTAG signals are asserted low (except STRSTn signals, which are high) and do not toggle. In configuration mode, the master has access to the configuration registers in the Switch TAP Controller. When EREQ is asserted low and a Secondary Port Selection Register (SPSR) address from 1 to 18 is selected, the selected secondary port JTAG signal group follows the ETM signals. The Switch TAP Controller operates as an IEEE 1149.1 TAP controller. Instructions can be written and registers written or read using the 1149.1 state diagram. The Switch TAP Controller uses the inverted ECFG signal as reset. 25
__________________________________________________________________________________________DS26900 It can also be reset by asserting ETMS high for at least six clock cycles. The Switch TAP Controller should be returned to the Test-Logic-Reset or Run-Test/Idle state before asserting ECFG high. To communicate with a particular secondary port, an address from 1 to 18 must be written into the 5-bit Secondary Port Selection Register (SPSR) during the configuration mode. This address does not change unless it is overwritten. However, toggling global rest (RST) sets the Secondary Port Selection Register (SPSR) to 00000b. An address of 00000b in the Secondary Port Selection Register (SPSR) (or any nonvalid port address) blocks communications to all slave ports. Only one secondary port can be selected at a time.
4.7
Switch Configuration by Test Master 1 or Test Master 2
The master arbitration circuit determines which test master has priority. Test Master 1 (TM1) or Test Master 2 (TM2) configures the switch by asserting its TMREQn low and TRSTn low. Access to the switch's configuration mode is accomplished by asserting TRSTn low. While in configuration mode, the secondary slave ports' JTAG signals are asserted low (except STRSTn signals, which are high) and do not toggle. In configuration mode, the master has access to the configuration registers in the Switch TAP Controller in the DS26900. When TREQn is asserted low and a Secondary Port Selection Register (SPSR) address from 1 to 18 (34) is selected, the secondary port JTAG signal group toggles normally and the arbitrated test master acts as the master. The Switch TAP Controller operates as a IEEE 1149.1 TAP controller. Instructions can be written and registers written or read using the 1149.1 state diagram. The Switch TAP Controller uses the inverted TRSTn signal as reset. It can also be reset by asserting TMSn high for at least six clock cycles. The Switch TAP Controller should be returned to the Test-Logic-Reset or Run-Test/Idle state before asserting TRSTn high. To communicate with a particular secondary port, an address from 1 to 18 must be written into the 5-bit Secondary Port Selection Register (SPSR) during the configuration mode. This address does not change unless it is overwritten. However, toggling global rest (RST) sets the Secondary Port Selection Register (SPSR) to 00000b. An address of 00000b in the Secondary Port Selection Register (SPSR) (or any nonvalid port address) blocks communications to all slave ports. Only one secondary port can be selected at any time.
26
__________________________________________________________________________________________DS26900
5. Resets
5.1 Global Reset Usage
The global reset, RST pin, does not affect the state machine logic of the Switch TAP Controller. The RST pin resets all other read and/or write registers.
5.2
Secondary Port Resets
The reset pins for secondary ports are always logic 1 unless the PORT_RST or the ALL_PORTS_RST instruction is set in configuration mode. When the PORT_RST instruction is loaded, the valid ports STRSTn is asserted logic 0 for three master TCLKs before returning to logic 1. When the ALL_PORTS_RST instruction is loaded, all valid STRSTn signals are asserted logic 0 for three master TCLKs before returning to logic 1. When not in configuration mode, the secondary ports STRSTn signals are always logic 1.
27
__________________________________________________________________________________________DS26900
6. Configuration Mode
Configuration mode is used by a master to program the options in the DS26900 switch and to configure the address of the secondary port. Configuration mode for the ETM is accomplished when EREQ and ECFG are both asserted low. While EREQ and ECFG are asserted low, the secondary slave ports JTAG signals are not allowed to toggle (STRSTn can only be asserted low by the Switch TAP Controller port reset instructions). In configuration mode, the master has access to the configuration TAP controller in the DS26900. When EREQ is asserted low and ECFG is asserted high, the JTAG signal group toggles normally and the ETM acts as the master. Configuration mode for the Test Master 1 and Test Master 2 is accomplished when TREQn and TRSTn are both asserted low. While TMREQ and TRSTn are both asserted low, the JTAG signal group remains static. In configuration mode, the master has access to the configuration TAP controller in the DS26900. To set the target (slave) port, the port address must be written to the Secondary Port Selection Register (SPSR). There is only one configuration mode for the DS26900. As a result, the master can set a configuration that remains valid for any master secondary port until reconfigured or RST is asserted low.
6.1
Switch TAP Controller
The Switch TAP Controller is implemented as standard IEEE 1149.1 TAP controller. See Section 9.2 and Figure 9-2. 6.1.1 Switch Instructions
Table 6-1. Switch TAP Instruction Codes
INSTRUCTIONS IDCODE PORT_DET PORT_SEL GPIO_CFG GPIO_READ CONFIG SCRATCH_1 SCRATCH_2 PORT_RST NOP ALL_PORTS_RST SELECTED REGISTER ID Register (IDR) Port Detection Register (PDR) Secondary Port Selection Register (SPSR) GPIO Configuration and Write Register (GPIOCR) GPIO Read Register (GPIORR) Device Configuration Register (DCR) Scratchpad 1 Register (SPR1) Scratchpad 2 Register (SPR2) Port Reset for a Selected Port No Operation Global Port Test Reset SINGLE-PACKAGE AND CASCADE MASTER INSTRUCTION CODES 00000 00001 00010 00011 00100 00101 00110 00111 01000 01001-01110 01111 CASCADE EXTENSION INSTRUCTION CODES 10000 10001 10010 10011 10100 10101 10110 10111 11000 11001-11110 11111
When performing a register write, the current value of a register is shifted out while the new register value is being shifted in. For read-only registers, some bit value must be shifted in (which is ignored) to shift out the current register value.
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__________________________________________________________________________________________DS26900 The MSB of the instruction code acts as an address bit. When in cascade configuration, the cascade master's TDO output and port communications is enabled only when the instruction MSB is 0. The cascade extension's TDO output and port communications is enabled only when the instruction MSB is 1. In Single-Package Mode, TDO output and port communications is enabled only when the instruction MSB is 0. 6.1.1.1 IDCODE
The IDCODE instruction allows access to the ID Register (IDR). The IDR register is an 8-bit read-only register that contains the revision code for the DS26900 in the lower 4 bits and a fixed 4-bit code in the upper 4 bits. This is identical to the revision code of the ID code, which is used for the periphery boundary scan. The IDR register is read-only. Writes to this register are ignored. 6.1.1.2 PORT_DET
The PORT_DET instruction initiates the sensing of the presence of secondary ports and allows access to the 20-bit Port Detection Register (PDR). The process of port detection temporarily changes the STMSn bidirectional pin outputs to inputs, senses which ports read as logical 1 (ports should have a 10k resistive pullup on their STMSn pin and the DS26900 has a 20k pulldown), and saves the results to the PDR register. Then the user must wait in the Run-Test-Idle state for a period of time to allow the voltage on the STMS pin to settle, typically 100ms. A "1" in a bit position indicates that logic 1 was sensed on that port's STMS pin. However, due to implementation variables, logic 0 in a bit position does not necessarily imply that a device is not attached to that port (the port STMS pin must have a pullup on STMS in order to be sensed). The PDR register inputs are level sensitive and are sampled after the PORT_DET instruction is loaded. The values in this register do not affect the operation of the DS26900. Port detection works for single-package and the two-package cascade configuration. Writes to this register are ignored. 6.1.1.3 PORT_SEL
The PORT_SEL instruction allows access to the 5-bit read/write Secondary Port Selection Register (SPSR). Writing a value to this register selects a port with which to communicate. Valid addresses are from 00001b (port one selected) to 10100b (TMS2). Addresses greater than 10100b and address 00000b do not select a port. Selecting an empty or nonexistent port has no adverse effect on the device, and no secondary port signals will toggle. 6.1.1.4 GPIO_CFG
The GPIO_CFG instruction allows access to the 8-bit read/write GPIO Configuration and Write Register (GPIOCR). The four GPIO pins can be individually configured to be an input, output logic 1, or output logic 0. The values, which are sensed on the pins, are available in the GPIO Read Register (GPIORR) via the GPIO_READ instruction. After global reset, the GPIO Configuration and Write Register (GPIOCR) bits are set to 00000000b and the GPIO pins are set to input mode. 6.1.1.5 GPIO_READ
The GPIO_READ instruction allows access to the 4-bit read-only GPIO Read Register (GPIORR). A "1" in a bit position indicates that logic 1 was sensed on that input's GPIO pin, and a "0" in a bit position indicates that logic 0 was sensed on that GPIO pin. If a pin was configured as an output, the register bit indicates the value being output. Writes to this register are ignored. The GPIO inputs are level sensitive and are sampled after the GPIO_READ instruction is loaded. GPIO pins that are configured as outputs are always read in this register as the value that is being output. After reset, the GPIO Read Register (GPIORR) bits are set to 0000b until a GPIO_READ instruction is given. Writes to this register are ignored. 6.1.1.6 CONFIG
The CONFIG instruction allows access to the 6-bit read/write Device Configuration Register (DCR). The DCR register controls options such as path and signaling inversions and the default deselected port drive values. 6.1.1.7 SCRATCH_1
The SCRATCH_1 instruction allows access to the 32-bit read/write Scratchpad 1 Register (SPR1). The SPR1 register is a user storage location, which is reset by the global reset signal. The values stored in this register do not affect the operation of the DS26900. 29
__________________________________________________________________________________________DS26900 6.1.1.8 SCRATCH_2
The SCRATCH_2 instruction allows access to the 32-bit read/write Scratchpad 2 Register (SPR2). The SPR2 register is a user storage location, which is reset by the global reset signal. The values stored in this register do not affect the operation of the DS26900. 6.1.1.9 PORT_RST
The PORT_RST instruction generates a port-specific STRSTn signal. Port selection must first be performed by loading an address into the Secondary Port Selection Register (SPSR). The selected STRSTn signal is asserted high, asserted low for three (TCLK) clock periods, and then is asserted high. If the SPSR register contains 00000b or an invalid address, no port reset is generated. The three-clock-period width is a fixed value. Exit from configuration mode before three clock periods have elapsed can shorten the width of this pulse. 6.1.1.10 NOP The NOP instruction is "no operation." It does not perform a function. 6.1.1.11ALL_PORTS_RST The ALL_PORTS_RST instruction generates a STRSTn signal to all possible 18 (or 20) ports simultaneously. All STRSTn signals start by being asserted high, asserted low for three (TCLK) clock periods, and then asserted high. The three-clock-period width is a fixed value. Exit from configuration mode before three clock periods have elapsed can shorten the width of this pulse.
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7. Device Registers Table 7-1. DS26900 List of Registers
REGISTER NAME IDR DCR GPIOCR GPIORR PDR SPSR SPR1 SPR2 SIZE (BITS) 8 6 8 4 20 5 32 32 FUNCTION Device Identification and Revision Code Register Device Configuration Register GPIO Configuration and Write Register GPIO Read Register Port Detection Register Secondary Port Selection Register Scratchpad Register 1 Scratchpad Register 2
Register Name: Register Description: Bit # Name Reset 7 ID7 1 6 ID6 1
IDR 8-Bit Device Identification and Revision Code Register 5 ID5 0 4 ID4 0 3 ID3 Revid[3] 2 ID2 Revid[2] 1 ID1 Revid[1] 0 ID0 Revid[0]
Bits 7 to 4: (ID[7:4]) Fixed binary pattern. Bits 3 to 0: (ID[3:0]). Bit revision ID.
31
__________________________________________________________________________________________DS26900 Register Name: Register Description: Bit # Name Reset 7 -- -- 6 -- -- DCR 6-Bit Device Configuration Register 5 TM_SLAVE 0 4 DPDV 0 3 TMSi 0 2 TDIi 0 1 TDOi 0 0 TCKi 0
Bit 5: Test Master Slave Enable (TM_SLAVE). Determines in conjunction with M[1:0] if the DS26900 device will drive nonmaster TM1/TM2 as slaves. If the TM buses are in parallel with more than one DS26900, only one DS26900 can drive TM1/TM2 as a slave. The following table describes the combinations. MODE Single-Package Single-Package Cascade Master Cascade Extension Deselect M[1:0] 00 00 01 10 11 TM_SLAVE BIT 0 1 N/A N/A N/A TM1/TM2 SLAVE CAPABLE No Yes Yes No N/A
Bit 4: Deselected Port Drive Values (DPDV). This bit determines the logic levels driving a deselected secondary port according to the following table. Note: This configuration bit does not apply to TM1 or TM2 in slave mode. TM1 or TM2 port signals in slave mode will never be high impedance. A secondary port is not selected (deselected) when device is in switch configuration mode, or when the particular port address is not loaded in the Secondary Port Selection Register (SPSR). The state of this bit can be monitored via the DPDV pin. SIGNAL STMSn STRSTn STDIn STCKn DPDV = 0 0 1 0 0 DPDV = 1 HiZ* 1 HiZ* 0
*HiZ is a high-impedance state with no internal pullup/down resistors active. Bit 3: Test Mode Select Invert (TMSi). Invert the TMS signal from the arbitrated master to the selected slave port by setting this bit to logic 1. Bit 2: Test Data In Invert (TDIi). Invert the TDI signal from the arbitrated master to the selected slave port by setting this bit to logic 1. Bit 1: Test Data Out Invert (TDOi). Invert the TDO signal from the selected slave port to the arbitrated master by setting this bit to logic 1. Bit 0: Test Clock Invert (TCKi). Invert the TCK from the arbitrated master to the selected slave port by setting this bit to logic 1.
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__________________________________________________________________________________________DS26900 Register Name: Register Description: Bit # Name Reset 7 GPIO3[1] 0 GPIOCR 8-Bit GPIO Configuration and Write Register 6 GPIO3[0] 0 5 GPIO2[1] 0 4 GPIO2[0] 0 3 GPIO1[1] 0 2 GPIO1[0] 0 1 GPIO0[1] 0 0 GPIO0[0] 0
Bit 7: GPIO3 Configuration Bit 1 (GPIO3[1]) GPIOn[1] 0 0 1 1 GPIOn[0] 0 1 0 1 GPIOn PIN MODE Input Output logic 0 Output logic 1 Reserved
Bit 6: GPIO3 Configuration Bit 0 (GPIO3[0]) Bit 5: GPIO2 Configuration Bit 1 (GPIO2[1]) Bit 4: GPIO2 Configuration Bit 0 (GPIO2[0]) Bit 3: GPIO1 Configuration Bit 1 (GPIO1[1]) Bit 2: GPIO1 Configuration Bit 0 (GPIO1[0]) Bit 1: GPIO0 Configuration Bit 1 (GPIO0[1]) Bit 0: GPIO0 Configuration Bit 0 (GPIO0[0])
Register Name: Register Description: Bit # Name Reset 7 -- -- 6 -- --
GPIORR 4-Bit GPIO Read Register 5 -- -- 4 -- -- 3 IN[3] 0 2 IN[2] 0 1 IN[1] 0 0 IN[0] 0
Bit 3: GPIO3 Input Value (IN[3]) Bit 2: GPIO2 Input Value (IN[2]) Bit 1: GPIO1 Input Value (IN[1]) Bit 0: GPIO0 Input Value (IN[0])
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__________________________________________________________________________________________DS26900 Register Name: Register Description: PDR 20-Bit Port Detection Register (Read-Only)
Bit # Name Reset
23 -- --
22 -- --
21 -- --
20 -- --
19 PORT20 (TM2 SLAVE) 0
18 PORT19 (TM1 SLAVE) 0
17 PORT18 0
16 PORT17 0
Bit # Name Reset Bit # Name Reset
15 PORT16 0 7 PORT8 0
14 PORT15 0 6 PORT 7 0
13 PORT14 0 5 PORT6 0
12 PORT13 0 4 PORT5 0
11 PORT12 0 3 PORT4 0
10 PORT11 0 2 PORT3 0
9 PORT10 0 1 PORT2 0
8 PORT9 0 0 PORT1 0
Bits 19 and 18: Port Detection (PORT[20:19]). If the TMS signal on PORTn has a 10k pullup resistor, a value of 1 is recorded in the bit location corresponding to PORTn. The Switch TAP Controller instruction PORT_DET instruction triggers the port detection action. Detection is also determined by the settings of the M[1:0] pins and the TM_SLAVE configuration bit. Bits 17 to 0: Port Detection (PORT[18:1]). If the TMS signal on PORTn has a 10k pullup resistor, a value of 1 is recorded in the bit location corresponding to PORTn. The Switch TAP Controller instruction PORT_DET instruction triggers the port detection action.
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__________________________________________________________________________________________DS26900 Register Name: Register Description: Bit # Name Reset 7 -- -- 6 -- -- SPSR 5-Bit Secondary Port Selection Register 5 -- -- 4 SSP[4] 0 3 SSP[3] 0 2 SSP[2] 0 1 SSP[1] 0 0 SSP[0] 0
Bits 4 to 0: Secondary Port Selection (SSP[4:0]). Port address (see Table 7-2).
Table 7-2. Secondary Port Selection Bits and Indicator Pins
SSP[4:0] BITS 00000 00001 00010 00011 00100 00101 00110 00111 01000 01001 01010 01011 01100 01101 01110 01111 10000 10001 10010 10011 10100 10101-11111 SELECTED PORT No Port Selected Port 1 Port 2 Port 3 Port 4 Port 5 Port 6 Port 7 Port 8 Port 9 Port 10 Port 11 Port 12 Port 13 Port 14 Port 15 Port 16 Port 17 Port 18 Port 19* (TM1 Slave Mode) Port 20* (TM2 Slave Mode) No Port Selected SSPI[4:0] PINS 11111 11110 11101 11100 11011 11010 11001 11000 10111 10110 10101 10100 10011 10010 10001 10000 01111 01110 01101 01100 01011 11111
*Ports 19 and 20 are only available if TM1 and/or TM2 are available to be driven in slave mode.
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__________________________________________________________________________________________DS26900 Register Name: Register Description: Bit # Name Reset Bit # Name Reset Bit # Name Reset Bit # Name Reset 31 SR1[31] 0 23 SR1[23] 0 15 SR1[15] 0 7 SR1[7] 0 SPR1 32-Bit Scratchpad Register 1 30 SR1[30] 0 22 SR1[22] 0 14 SR1[14] 0 6 SR1[6] 0 29 SR1[29] 0 21 SR1[21] 0 13 SR1[13] 0 5 SR1[5] 0 28 SR1[28] 0 20 SR1[20] 0 12 SR1[12] 0 4 SR1[4] 0 27 SR1[27] 0 19 SR1[19] 0 11 SR1[11] 0 3 SR1[3] 0 26 SR1[26] 0 18 SR1[18] 0 10 SR1[10] 0 2 SR1[2] 0 25 SR1[25] 0 17 SR1[17] 0 9 SR1[9] 0 1 SR1[1] 0 24 SR1[24] 0 16 SR1[16] 0 8 SR1[8] 0 0 SR1[0] 0
Bits 31 to 0: Scratchpad Register 1 Bits 31 to 0 (SR1[31:0])
Register Name: Register Description: Bit # Name Reset Bit # Name Reset Bit # Name Reset Bit # Name Reset 31 SR2[31] -- 23 SR2[23] -- 15 SR2[15] -- 7 SR2[7] --
SPR2 32-Bit Scratchpad Register 2 30 SR2[30] -- 22 SR2[22] -- 14 SR2[14] -- 6 SR2[6] -- 29 SR2[29] -- 21 SR2[21] -- 13 SR2[13] -- 5 SR2[5] -- 28 SR2[28] -- 20 SR2[20] -- 12 SR2[12] -- 4 SR2[4] -- 27 SR2[27] -- 19 SR2[19] -- 11 SR2[11] -- 3 SR2[3] -- 26 SR2[26] -- 18 SR2[18] -- 10 SR2[10] -- 2 SR2[2] -- 25 SR2[25] -- 17 SR2[17] -- 9 SR2[9] -- 1 SR2[1] -- 24 SR2[24] -- 16 SR2[16] -- 8 SR2[8] -- 0 SR2[0] --
Bits 31 to 0: Scratchpad Register 2 Bits 31 to 0 (SR2[31:0])
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8. Additional Application Information
8.1 Accessing Individual Device JTAG on a Board
The DS26900 can be used to provide access to individual device JTAG chains on a board. For this configuration, TMREQ1 and TMREQ2 are tied high and EREQ is tied low, yielding a single-master configuration with a 5-pin interface. Individual subports on the DS26900 can be selected in configuration mode.
8.2
Using LED Indicators on the SSPI, ACT and MCI Pins
LED indicators can be attached to the MCI, ACT, and/or SSPI[4:0] pins by connecting the anode of the LED to VDD via a series resistor and the cathode connected to the appropriate DS26900 pin. Series resistance should be no less than approximately 175 to limit current to 8mA.
8.3
Using 2.7V and 1.8V Logic Levels with the DS26900
The DS26900 operates at a nominal supply voltage of 3.3V. The input buffers are designed to switch at midrail (VDD/2 = ~1.65V) with some hysteresis. This allows the input buffers the ability to sense 2.7V and 1.8V CMOS logic levels without modification or configuration in some applications. With that in mind, compatibility with 2.7V and 1.8V CMOS logic levels (other than 3.3V CMOS logic level) is not expressly guaranteed. The output buffers are capable of 3.3V CMOS (rail-to-rail) logic levels.
8.4
Series Termination Resistors
Although not part of the IEEE 1149.1 specification, some PCB designs require series termination of clock signals at the electrical source. For the DS26900, the recommended typical series termination value for outputs is 33. This value can vary depending on the PCB's trace geometries.
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9. Periphery JTAG
9.1 Periphery JTAG Description
The DS26900 contains traditional boundary scan circuitry at the periphery of the package for board manufacturing tests. This periphery boundary scan circuitry is independent and has priority over the operation of the master/slave multiplexer. It contains a separate TAP controller with a 3-bit wide instruction code register. Signals associated with the periphery boundary scan circuitry are PTRST, PTMS, PTCK, PTDI, and PTDO. The DS26900 supports the standard instruction codes SAMPLE/PRELOAD, BYPASS, and EXTEST. Optional public instructions included are HIGHZ, CLAMP and IDCODE. See Figure 9-1 for a block diagram. The DS26900 contains the following items, which meet the requirements set by the IEEE 1149.1 Standard Test Access Port and Boundary Scan Architecture: Test Access Port (TAP) TAP Controller Instruction Register Bypass Register Boundary Scan Register Device Identification Register
Details on the Boundary Scan Architecture and the Test Access Port can be found in IEEE 1149.1-2001, IEEE 1149.1-1990, IEEE 1149.1a-1993, and IEEE 1149.1b-1994. Figure 9-1. Periphery JTAG Block Diagram
BOUNDARY SCAN REGISTER IDENTIFICATION REGISTER BYPASS REGISTER INSTRUCTION REGISTER
SELECT
TEST ACCESS PORT CONTROLLER
TRI-STATE
10k
10k
10k
PTDI
PTMS
PTCLK
PTRST
MUX
PTDO
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9.2
JTAG TAP Controller State Machine Description
This section covers the details on the operation of the Test Access Port (TAP) Controller State Machine. See Figure 9-2 for details on each of the states described. The TAP controller is a finite state machine that responds to the logic level at PTMS on the rising edge of PTCLK. Figure 9-2. JTAG TAP Controller State Machine
Test-Logic-Reset 1 0 1 Select DR-Scan 0 1 Capture-DR 0 Shift-DR 0 1 Exit1- DR 0 Pause-DR 0 1 0 Exit2-DR 1 Update-DR 1 0 1 0 1 Exit2-IR 1 Update-IR 0 1 1 Exit1-IR 0 Pause-IR 0 1 1 Capture-IR 0 Shift-IR 0 1 Select IR-Scan 0 1
Run-Test/Idle 0
Test-Logic-Reset. Upon device power-up, the TAP controller starts in the Test-Logic-Reset state. The instruction register contains the IDCODE instruction. All system logic on the device operates normally. Run-Test-Idle. Run-Test-Idle is used between scan operations or during specific tests. The instruction register and test register remain idle. Select-DR-Scan. All test registers retain their previous state. With PTMS low, a rising edge of PTCLK moves the controller into the Capture-DR state and initiates a scan sequence. PTMS high moves the controller to the SelectIR-SCAN state. Capture-DR. Data can be parallel loaded into the test data registers selected by the current instruction. If the instruction does not call for a parallel load or the selected register does not allow parallel loads, the test register 39
__________________________________________________________________________________________DS26900 remains at its current value. On the rising edge of PTCLK, the controller goes to the Shift-DR state if PTMS is low or it to the Exit1-DR state if PTMS is high. Shift-DR. The test data register selected by the current instruction is connected between PTDI and PTDO and shifts data one stage towards its serial output on each rising edge of PTCLK. If a test register selected by the current instruction is not placed in the serial path, it maintains its previous state. Exit1-DR. While in this state, a rising edge on PTCLK with PTMS high puts the controller in the Update-DR state, which terminates the scanning process. A rising edge on PTCLK with PTMS low puts the controller in the PauseDR state. Pause-DR. Shifting of the test registers is halted while in this state. All test registers selected by the current instruction retain their previous state. The controller remains in this state while PTMS is low. A rising edge on PTCLK with PTMS high puts the controller in the Exit2-DR state. Exit2-DR. While in this state, a rising edge on PTCLK with PTMS high puts the controller in the Update-DR state and terminates the scanning process. A rising edge on PTCLK with PTMS low puts the controller in the Shift-DR state. Update-DR. A falling edge on PTCLK while in the Update-DR state latches the data from the shift register path of the Test registers into the data output latches. This prevents changes at the parallel output due to changes in the shift register. A rising edge on PTCLK with PTMS low puts the controller in the Run-Test-Idle state. With PTMS high, the controller enters the Select-DR-Scan state. Select-IR-Scan. All test registers retain their previous state. The instruction register remains unchanged during this state. With PTMS low, a rising edge on PTCLK moves the controller into the Capture-IR state and initiates a scan sequence for the Instruction register. PTMS high during a rising edge on PTCLK puts the controller back into the Test-Logic-Reset state. Capture-IR. The Capture-IR state is used to load the shift register in the Instruction register with a fixed value. This value is loaded on the rising edge of PTCLK. If PTMS is high on the rising edge of PTCLK, the controller enters the Exit1-IR state. If PTMS is low on the rising edge of PTCLK, the controller enters the Shift-IR state. Shift-IR. In this state, the shift register in the instruction register is connected between PTDI and PTDO and shifts data one stage for every rising edge of PTCLK towards the serial output. The parallel register, as well as all test registers, remains at its previous states. A rising edge on PTCLK with PTMS high moves the controller to the Exit1IR state. A rising edge on PTCLK with PTMS low keeps the controller in the Shift-IR state while moving data one stage through the Instruction shift register. Exit1-IR. A rising edge on PTCLK with PTMS low puts the controller in the Pause-IR state. If PTMS is high on the rising edge of PTCLK, the controller enters the Update-IR state and terminates the scanning process. Pause-IR. Shifting of the Instruction register is halted temporarily. With PTMS high, a rising edge on PTCLK puts the controller in the Exit2-IR state. The controller remains in the Pause-IR state if PTMS is low during a rising edge on PTCLK. Exit2-IR. A rising edge on PTCLK with PTMS high put the controller in the Update-IR state. The controller loops back to the Shift-IR state if PTMS is low during a rising edge of PTCLK in this state. Update-IR. The instruction shifted into the instruction shift register is latched into the parallel output on the falling edge of PTCLK as the controller enters this state. Once latched, this instruction becomes the current instruction. A rising edge on PTCLK with PTMS low, puts the controller in the Run-Test-Idle state. With PTMS high, the controller enters the Select-DR-Scan state.
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9.3
JTAG Instruction Register and Instructions
The instruction register contains a shift register as well as a latched parallel output and is 3 bits in length. When the TAP controller enters the Shift-IR state, the instruction shift register is connected between PTDI and PTDO. While in the Shift-IR state, a rising edge on PTCLK with PTMS low shifts data one stage towards the serial output at PTDO. A rising edge on PTCLK in the Exit1-IR state or the Exit2-IR state with PTMS high moves the controller to the Update-IR state. The falling edge of that same PTCLK latches the data in the instruction shift register to the instruction parallel output. Instructions supported by the DS26900 and their respective operational binary codes are shown in Table 9-1.
Table 9-1. Periphery JTAG Instruction Codes
INSTRUCTIONS SAMPLE/PRELOAD BYPASS EXTEST CLAMP HIGHZ IDCODE 9.3.1 SAMPLE/PRELOAD This is a mandatory instruction for the IEEE 1149.1 specification. This instruction supports two functions. The digital I/Os of the device can be sampled at the boundary scan register without interfering with the normal operation of the device by using the Capture-DR state. SAMPLE/PRELOAD also allows the DS26900 to shift data into the boundary scan register via PTDI using the Shift-DR state. 9.3.2 EXTEST EXTEST allows testing of all interconnections to the device. When the EXTEST instruction is latched in the instruction register, the following actions occur. Once enabled via the Update-IR state, the parallel outputs of all digital output pins are driven. The boundary scan register is connected between PTDI and PTDO. The Capture-DR samples all digital inputs into the boundary scan register. 9.3.3 BYPASS When the BYPASS instruction is latched into the parallel Instruction register, PTDI connects to PTDO through the 1-bit bypass test register. This allows data to pass from PTDI to PTDO not affecting the device's normal operation. 9.3.4 IDCODE When the IDCODE instruction is latched into the parallel Instruction register, the identification test register is selected. The device identification code is loaded into the Identification register on the rising edge of PTCLK following entry into the Capture-DR state. Shift-DR can be used to shift the identification code out serially via PTDO. During Test-Logic-Reset, the identification code is forced into the instruction register's parallel output. The device ID code always has a one in the LSB position. The next 11 bits identify the manufacturer's JEDEC number and number of continuation bytes followed by 16 bits for the device and 4 bits for the version. The device ID code for the DS26900 is 0008D143. 9.3.5 HIGHZ All digital outputs are placed into a high-impedance state. The bypass register is connected between PTDI and PTDO. 41 SELECTED REGISTER Boundary Scan Bypass Boundary Scan Bypass Bypass Device Identification INSTRUCTION CODES 010 111 000 011 100 001
__________________________________________________________________________________________DS26900 9.3.6 CLAMP All digital outputs pins output data from the boundary scan parallel output while connecting the bypass register between PTDI and PTDO. The outputs do not change during the CLAMP instruction.
9.4
JTAG Test Registers
IEEE 1149.1 requires a minimum of two test registers: the bypass register and the boundary scan register. An optional test register has been included in the device design. This test register is the identification register, and is used in conjunction with the IDCODE instruction and the Test-Logic-Reset state of the TAP controller. 9.4.1 Bypass Register This is a single 1-bit shift register used in conjunction with the BYPASS, CLAMP, and HIGHZ instructions, which provides a short path between PTDI and PTDO. 9.4.2 Identification Register The Identification register contains a 32-bit shift register and a 32-bit latched parallel output. This register is selected during the IDCODE instruction and when the TAP controller is in the Test-Logic-Reset state. 9.4.3 Boundary Scan Register This register contains both a shift register path and a latched parallel output for all control cells and digital I/O cells and is 361 bits in length.
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10.
Operating Parameters
ABSOLUTE MAXIMUM RATINGS Voltage Range on Any Lead with Respect to VSS (except VDD) .....................................................-0.3V to 5.5V Supply Voltage Range (VDD) with Respect to VSS ....................................................................-0.3V to 3.63V Operating Temperature Range ...........................................................................................-40C to +85C Storage Temperature Range ............................................................................................-55C to +126C Soldering Temperature..................................................................See IPC/JEDEC J-STD-020 specification.
This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability.
10.1 Thermal Information
Table 10-1. Thermal Characteristics
PARAMETER Target Ambient Temperature Range Die Junction Temperature Range Theta-JC (Junction to Top of Case) Theta-JB (Junction to Bottom Pins) Theta-JA, Still Air 100 LFM Theta-JA 200 LFM 500 LFM VALUE -40C to +85C -40C to +126C 10C/W 10C/W 22C/W (Note 1) 20C/W (Note 1) 17C/W (Note 1) 15C/W (Note 1)
Note 1: Theta-JA values are estimates using JEDEC-standard PCB and enclosure dimensions.
10.2 DC Characteristics
Table 10-2. Recommended DC Operating Conditions
(TA = -40C to +85C)
PARAMETER Logic 1 Logic 0 Supply (VDD) SYMBOL VIH VIL VDD MIN 2.4 -0.3 3.135 TYP MAX 4.2 0.8 3.465 UNITS V V V
Table 10-3. DC Electrical Characteristics
(VDD = 3.3V 5%, TA = -40C to +85C.)
PARAMETER Supply Current (VDD = 3.465V) Lead Capacitance Input Leakage Input Pins with Internal Pullup Resistors Output Current (2.4V) Output Voltage (IOH = -4.0mA) Output Voltage (IOH = +4.0mA) Output Current (0.4V) SYMBOL IDD CIO IIL IILP IOH VOH VOL IOL +4.0 -10 -250 -4.0 2.4 0.4 MIN TYP 15 7 +10 +10 MAX UNITS mA pF A A mA V V mA 43
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11.
AC Timing
Unless otherwise noted, all timing numbers assume 20pF test load on output signals, 40pF test load on bus signals.
11.1 Switch TAP Controller Interface Timing
Table 11-1. Switch TAP Controller Interface Timing
(VDD = 3.3V 5%, TA = -40C to +85C.) (See Figure 11-1.)
PARAMETER ETCK, TCK1, TCK2 Clock Period ETCK, TCK1, TCK2 Clock Low Time ETCK, TCK1, TCK2 Clock High Time ETCK to ETDI, ETMS Setup Time TCK1 to TDI1, TMS1 Setup Time TCK2 to TDI2, TMS2 Setup Time ETCK to ETDI, ETMS Hold Time TCK1 to TDI1, TMS1 Hold Time TCK2 to TDI2, TMS2 Hold Time ETCK to ETDO Delay TCK1 to TDO1 Delay TCK2 to TDO2 Delay ETCK to ETDO High-Impedance Delay TCK1 to TDO1 High-Impedance Delay TCK2 to TDO2 High-Impedance Delay
Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: TCK should be stopped low. Interface timing in Table 11-1 is to/from the arbitrated master. TCK corresponds to each master port clock when being used to configure the core JTAG controller, e.g., ETCK or TCK1 or TCK2. TDI, TMS correspond to the master port TDI, TMS when being used to configure the core JTAG controller, e.g., ETDI, ETMS or TDI1, TMS1 or TDI2, TMS2. TDO corresponds to the master port TDO when being used to configure the core JTAG controller, e.g., ETDO or TDO1 or TDO2. The configuration signals (TRST1, TRST2, ECFG) and the master request signals (TMREQ1, TMREQ2, EREQ) are asynchronous. TCK, TDI, TMS should be low when switching masters to avoid the possibility of glitching the secondary port whose address is in the Secondary Port Selection Register (SPSR). Another method to avoid glitching the secondary port is to set the Secondary Port Selection Register (SPSR) to 00000 when changing the arbitrated master.
SYMBOL t1 t2 t3 t4
MIN 25 17.5 7.5 3
TYP
MAX
UNITS ns ns ns ns
NOTES 30% DC
t5
3
ns
t6
15
ns
t7
17.5
ns
Figure 11-1. Switch TAP Controller Interface Timing Diagram
T1 T2 ETCK TCK1 TCK2 T4 ETDI, ETMS TDI1, TMS1 TDI2, TMS2 T7 T6 ETDO TDO1 TDO2 T5 T3
44
__________________________________________________________________________________________DS26900
11.2 Transparent Mode Master/Slave Port Timing
Table 11-2. Master/Slave Port Timing
(VDD = 3.3V 5%, TA = -40C to +85C.) (See Figure 11-2.)
PARAMETER ETCK, TCLK1, TCLK2 to STCKx Latency ETMS, TMS1, TMS2 to STMSx Latency ETDI, TDI1, TDI2 to STDIx Latency ETCK, TCLK1, TCLK2 to STCKx Skew ETMS, TMS1, TMS2 to STMSx Skew ETDI, TDI1, TDI2 to STDIx Skew STDOx to ETDO, TDO1, TDO2 Latency TDO + TCK
Note 1: Note 2: Note 3: Note 4: Note 5: Note 6:
SYMBOL t1
MIN 3
TYP
MAX 11
UNITS ns
NOTES 1
t2 t3 t5
0.8 3 11.4
4.0 11 26.4
ns ns ns
2, 3 4 5
16
Delay (latency) from a particular master port signal to the corresponding slave port signal. Skew values are with respect to a signal from the arbitrated master to the same signal on the selected secondary slave port. Skew from any set of two signals at a master port to the corresponding two signals at the selected slave port. Delay path from a selected slave port STDO to the arbitrated master's TDO. Half-cycle path from falling edge STCK/STDO (launch) to rising edge TCK/TDO (capture), pass-through path (see Figure 11-2). TCK corresponds to each master port clock when being used to configure the core JTAG controller, e.g., ETCK or TCK1 or TCK2. TDI, TMS correspond to the master port TDI, TMS, e.g., ETDI, ETMS or TDI1, TMS1 or TDI2, TMS2. TDO corresponds to the master port TDO when being used to configure the core JTAG controller, e.g., ETDO or TDO1 or TDO2. STCK corresponds to each slave port clock, e.g., STCK1-STCK18. STDI, STMS correspond to the slave port TDI, TMS, e.g., STDI1-STDI18, STMS1-STMS18. STDO corresponds to the slave port STDO1-STDO18.
Note 7:
Figure 11-2. Transparent Mode Master/Slave Port Timing Diagram
t5 ETCK, TCK1, TCK2 ETMS, TMS1, TMS2 ETDI, TDI1, TDI2 t1 STCKn, STMSn, STDIn t2
STDOn t3 ETDO, TDO1, TDO2 t4
45
__________________________________________________________________________________________DS26900
11.3 Periphery JTAG Interface Timing
Table 11-3. Periphery JTAG Interface Timing
(VDD = 3.3V 5%, TA = -40C to +85C.) (See Figure 11-3.)
PARAMETER PTCLK Clock Period PTCLK Clock High/Low Time PTCLK to PTDI, PTMS Setup Time PTCLK to PTDI, PTMS Hold Time PTCLK to PTDO Delay PTCLK to PTDO High-Impedance Delay PTRST Width Low Time
Note 1: Note 2:
SYMBOL t1 t2/t3 t4 t5 t6 t7 t8
MIN 100 30 20 10 2 2 50
TYP
MAX
UNITS ns ns ns ns
NOTES 1 2
10 10
ns ns ns
Clock period for the periphery boundary scan is 100ns (min). Clock can be stopped high or low.
Figure 11-3. Periphery JTAG Interface Timing Diagram
T1 T2 PTCLK T4 PTDI PTMS T7 T6 T5 T3
PTDO
PTRST T8
46
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12.
Pin Configuration
47
__________________________________________________________________________________________DS26900
13.
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. The package number provided for each package is a link to the latest package outline information.)
13.1 144-Pin LQFP (56-G6037-001)
48
__________________________________________________________________________________________DS26900
49
__________________________________________________________________________________________DS26900
14.
Document Revision History
DESCRIPTION New Product Release. 072707
REVISION
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
(c) 2007 Maxim Integrated Products
50
is a registered trademark of Maxim Integrated Products.


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