Datasheet SN74ABT18502PM Datasheet (Texas Instruments)

Download

Page 1

SN54ABT18502, SN74ABT18502

SCAN TEST DEVICES WITH

18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

• Members of the Texas Instruments

SCOPE

 Family of Testability Products

• Members of the Texas Instruments

Widebus

 Family

• Compatible With the IEEE Standard

1149.1-1990 (JTAG) Test Access Port and Boundary-Scan Architecture

•

UBT

 (Universal Bus Transceiver)

Combines D-Type Latches and D-Type Flip-Flops for Operation in Transparent, Latched, or Clocked Mode

• Two Boundary-Scan Cells per I/O for

Greater Flexibility

• State-of-the-Art

Significantly Reduces Power Dissipation

EPIC-ΙΙB

1A3 1A4 1A5

GND

1A6 1A7 1A8 1A9

2A1 2A2 2A3

GND

2A4 2A5 2A6

 BiCMOS Design

1A2

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

28 29 30 31 32 33 34

SN54ABT18502 . . . HV PACKAGE

1A1

1OEAB

GND

87 65493168672

1LEAB

1CLKAB

(TOP VIEW)

VNCTMS

TDO

35 36 37 38 39

•

SCOPE

 Instruction Set

– IEEE Standard 1149.1-1990 Required

Instructions, Optional INTEST, and P1149.1A CLAMP and HIGHZ

– Parallel Signature Analysis at Inputs With

Masking Option

– Pseudo-Random Pattern Generation

From Outputs – Sample Inputs/Toggle Outputs – Binary Count From Outputs – Device Identification – Even-Parity Opcodes

• Packaged in 64-Pin Plastic Thin Quad Flat

Pack Using 0.5-mm Center-to-Center Spacings and 68-Pin Ceramic Quad Flat Pack Using 25-mil Center-to-Center Spacings

1CLKBA

1LEBA

1OEBA

GND

1B1

1B2

1B3

66 652764 63 62 61

1B4

1B5

1B6

GND

1B7

1B8

1B9

2B1

2B2

2B3

2B4

GND

2B5

2B6

2B7

40 41 42 43

2LEAB

2CLKAB

TDI

TCK

2LEBA 2CLKBA

2A9

2A7

2A8

GND

2OEAB

NC – No internal connection

SCOPE, Widebus, UBT, and EPIC-IIB are trademarks of T exas Instruments Incorporated.

UNLESS OTHERWISE NOTED this document contains PRODUCTION DATA information current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters.

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

GND

2B9

2B8

2OEBA

Page 2

SN54ABT18502, SN74ABT18502 SCAN TEST DEVICES WITH 18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

1A3 1A4 1A5

GND

1A6 1A7 1A8 1A9

2A1 2A2 2A3

GND

2A4 2A5 2A6

SN74ABT18502 ...PM PACKAGE

1OEAB

1A2

1A1

63 62 61 60 5964 58 56 55 5457 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

18 19

GND

1CLKAB

1LEAB

21 22 23 24

(TOP VIEW)

TDO

TMS

25 26 27 28 29

1LEBA

1OEBA

1CLKBA

53 521751 50 49

1B1

GND

30 31 32

1B2

1B3

48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33

1B4 1B5 1B6 GND 1B7 1B8 1B9 V

2B1 2B2 2B3 2B4 GND 2B5 2B6 2B7

2LEAB

2CLKAB

TDI

TCK

2CLKBA

GND

2LEBA

2B9

2OEBA

2B8

2A7

2A8

2A9

GND

2OEAB

description

The SN54ABT18502 and SN74ABT18502 scan test devices with 18-bit universal bus transceivers are members of the T exas Instruments SCOPE testability IC family . This family of devices supports IEEE Standard

1149.1-1990 boundary scan to facilitate testing of complex circuit board assemblies. Scan access to the test circuitry is accomplished via the 4-wire test access port (TAP) interface.

In the normal mode, these devices are 18-bit universal bus transceivers that combine D-type latches and D-type flip-flops to allow data flow in transparent, latched, or clocked modes. They can be used either as two 9-bit transceivers or one 18-bit transceiver. The test circuitry can be activated by the TAP to take snapshot samples of the data appearing at the device pins or to perform a self test on the boundary test cells. Activating the T AP in the normal mode does not affect the functional operation of the SCOPE universal bus transceivers.

Data flow in each direction is controlled by output-enable (OEAB and clock (CLKAB and CLKBA) inputs. For A-to-B data flow, the device operates in the transparent mode when LEAB is high. When LEAB is low , the A-bus data is latched while CLKAB is held at a static low or high logic level. Otherwise, if LEAB is low, A-bus data is stored on a low-to-high transition of CLKAB. When OEAB is low, the B outputs are active. When OEAB

is high, the B outputs are in the high-impedance state. B-to-A data flow is

similar to A-to-B data flow but uses the OEBA, LEBA, and CLKBA inputs. In the test mode, the normal operation of the SCOPE universal bus transceivers is inhibited, and the test

circuitry is enabled to observe and control the I/O boundary of the device. When enabled, the test circuitry performs boundary scan test operations according to the protocol described in IEEE Standard 1149.1-1990.

and OEBA), latch-enable (LEAB and LEBA),

2 2

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 3

SN54ABT18502, SN74ABT18502

SCAN TEST DEVICES WITH

18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

description (continued)

Four dedicated test pins are used to observe and control the operation of the test circuitry: test data input (TDI), test data output (TDO), test mode select (TMS), and test clock (TCK). Additionally , the test circuitry can perform other testing functions such as parallel signature analysis on data inputs and pseudo-random pattern generation from data outputs. All testing and scan operations are synchronized to the TAP interface.

Additional flexibility is provided in the test mode through the use of two boundary scan cells (BSCs) for each I/O pin. This allows independent test data to be captured and forced at either bus (A or B). A PSA/COUNT instruction is also included to ease the testing of memories and other circuits where a binary count addressing scheme is useful.

The SN54ABT18502 is characterized for operation over the full military temperature range of –55°C to 125°C. The SN74ABT18502 is characterized for operation from –40°C to 85°C.

FUNCTION TABLE

(normal mode, each register)

INPUTS

OEAB LEAB CLKAB A

L L L X B L L ↑ LL L L ↑ HH L HXLL L HXHH

H X X X Z

†

A-to-B data flow is shown. B-to-A data flow is similar but uses OEBA

‡

Output level before the indicated steady-state input conditions were established.

, LEBA, and CLKBA.

†

OUTPUT

‡

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 4

SN54ABT18502, SN74ABT18502 SCAN TEST DEVICES WITH 18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

functional block diagram

Boundary-Scan Register

1LEAB

1CLKAB

1OEAB

1LEBA

1CLKBA

1OEBA

1A1

2LEAB

2CLKAB

2OEAB

2LEBA

2CLKBA

2OEBA

2A1

One of Nine Channels

C1 1D

1B1

2B1

TDI

TMS

TCK

Pin numbers shown are for the PM package.

4 4

Controller

Bypass Register

Boundary-Control

Identification

Instruction

TAP

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

TDO

Page 5

18-BIT REGISTERED BUS TRANSCEIVERS

Terminal Functions

PIN NAME DESCRIPTION

GND Ground

TCK

TDI

TDO

TMS V

1A1–1A9, 2A1–2A9

1B1–1B9, 2B1–2B9

1CLKAB, 1CLKBA,

2CLKAB, 2CLKBA

1LEAB, 1LEBA,

2LEAB, 2LEBA

1OEAB, 1OEBA,

, 2OEBA

2OEAB

Test clock. One of four pins required by IEEE Standard 1149.1-1990. Test operations of the device are synchronous to the test clock. Data is captured on the rising edge of TCK and outputs change on the falling edge of TCK.

T est data input. One of four pins required by IEEE Standard 1 149.1-1990. The test data input is the serial input for shifting data through the instruction register or selected data register. An internal pullup forces TDI to a high level if left unconnected.

Test data output. One of four pins required by IEEE Standard 1149.1-1990. The test data output is the serial output for shifting data through the instruction register or selected data register.

T est mode select. One of four pins required by IEEE Standard 1 149.1-1990. The test mode select input directs the device through its test access port (TAP) controller states. An internal pullup forces TMS to a high level if left unconnected.

Supply voltage Normal-function A-bus I/O ports. See function table for normal-mode logic.

Normal-function B-bus I/O ports. See function table for normal-mode logic.

Normal-function clock inputs. See function table for normal-mode logic.

Normal-function latch enables. See function table for normal-mode logic.

Normal-function output enables. See function table for normal-mode logic.

SN54ABT18502, SN74ABT18502

SCAN TEST DEVICES WITH

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 6

SN54ABT18502, SN74ABT18502 SCAN TEST DEVICES WITH 18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

test architecture

Serial test information is conveyed by means of a 4-wire test bus or test access port (T AP), that conforms to IEEE Standard 1 149.1-1990. Test instructions, test data, and test control signals are all passed along this serial test bus. The T AP controller monitors two signals from the test bus, namely TCK and TMS. The function of the T AP controller is to extract the synchronization (TCK) and state control (TMS) signals from the test bus and generate the appropriate on-chip control signals for the test structures in the device. Figure 1 shows the T AP controller state diagram.

The T AP controller is fully synchronous to the TCK signal. Input data is captured on the rising edge of TCK and output data changes on the falling edge of TCK. This scheme ensures that data to be captured is valid for fully one-half of the TCK cycle.

The functional block diagram illustrates the IEEE Standard 1149.1-1990 4-wire test bus and boundary-scan architecture and the relationship between the test bus, the T AP controller , and the test registers. As illustrated, the device contains an 8-bit instruction register and four test data registers: an 84-bit boundary-scan register, a 21-bit boundary-control register, a 1-bit bypass register, and a 32-bit device identification register.

Test-Logic-Reset

TMS = H

TMS = L

Run-Test/Idle Select-DR-Scan

TMS = L

Capture-DR

TMS = L

Shift-DR

TMS = L

TMS = H

Exit1-DR

TMS = L

Pause-DR

TMS = L

TMS = H

Exit2-DR

TMS = H

TMS = HTMS = H

TMS = H TMS = H

TMS = L

Select-IR-Scan

TMS = H

TMS = L

Capture-IR

TMS = L

Shift-IR

TMS = L

TMS = H

Exit1-IR

TMS = L

Pause-IR

TMS = L

TMS = H

Exit2-IR

TMS = H

Update-DR

TMS = LTMS = H

Update-IR

TMS = LTMS = H

Figure 1. TAP Controller State Diagram

6 6

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 7

SN54ABT18502, SN74ABT18502

SCAN TEST DEVICES WITH

18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

state diagram description

The test access port (TAP) controller is a synchronous finite state machine that provides test control signals throughout the device. The state diagram is illustrated in Figure 1 and is in accordance with IEEE Standard

1149.1-1990. The TAP controller proceeds through its states based on the level of TMS at the rising edge of TCK.

As illustrated, the T AP controller consists of sixteen states. There are six stable states (indicated by a looping arrow in the state diagram) and ten unstable states. A stable state is defined as a state the T AP controller can retain for consecutive TCK cycles. Any state that does not meet this criterion is an unstable state.

There are two main paths though the state diagram: one to access and control the selected data register and one to access and control the instruction register. Only one register can be accessed at a time.

Test-Logic-Reset

The device powers up in the Test-Logic-Reset state. In the stable Test-Logic-Reset state, the test logic is reset and is disabled so that the normal logic function of the device is performed. The instruction register is reset to an opcode that selects the optional IDCODE instruction, if supported, or the BYP ASS instruction. Certain data registers may also be reset to their power-up values.

The state machine is constructed such that the T AP controller returns to the Test-Logic-Reset state in no more than five TCK cycles if TMS is left high. The TMS pin has an internal pullup resistor that forces it high if left unconnected or if a board defect causes it to be open circuited.

For the ′ABT18502, the instruction register is reset to the binary value 10000001, which selects the IDCODE instruction. Each bit in the boundary-scan register is reset to logic 0 except bits 83–80, which are reset to logic 1. The boundary-control register is reset to the binary value 000000000000000000010, which selects the PSA test operation with no input masking.

Run-Test/Idle

The T AP controller must pass through the Run-T est/Idle state (from T est-Logic-Reset) before executing any test operations. The Run-Test/Idle state can also be entered following data register or instruction register scans. Run-Test/Idle is provided as a stable state in which the test logic may be actively running a test or can be idle.

The test operations selected by the boundary-control register are performed while the T AP controller is in the Run-Test/Idle state.

Select-DR-Scan, Select-lR-Scan

No specific function is performed in the Select-DR-Scan and Select-lR-Scan states, and the T AP controller exits either of these states on the next TCK cycle. These states are provided to allow the selection of either data register scan or instruction register scan.

Capture-DR

When a data register scan is selected, the TAP controller must pass through the Capture-DR state. In the Capture-DR state, the selected data register can capture a data value as specified by the current instruction. Such capture operations occur on the rising edge of TCK upon which the T AP controller exits the Capture-DR state.

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 8

SN54ABT18502, SN74ABT18502 SCAN TEST DEVICES WITH 18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

state diagram description (continued)

Shift-DR

Upon entry to the Shift-DR state, the data register is placed in the scan path between TDI and TDO and, on the first falling edge of TCK, TDO goes from the high-impedance state to an active state. TDO enables to the logic level present in the least significant bit of the selected data register.

While in the stable Shift-DR state, data is serially shifted through the selected data register on each TCK cycle. The first shift occurs on the first rising edge of TCK after entry to the Shift-DR state (i.e., no shifting occurs during the TCK cycle in which the T AP controller changes from Capture-DR to Shift-DR or from Exit2-DR to Shift-DR). The last shift occurs on the rising edge of TCK upon which the TAP controller exits the Shift-DR state.

Exit1-DR, Exit2-DR

The Exit1-DR and Exit2-DR states are temporary states used to end a data register scan. It is possible to return to the Shift-DR state from either Exit1-DR or Exit2-DR without recapturing the data register.

On the first falling edge of TCK after entry to Exit1-DR, TDO goes from the active state to the high-impedance state.

Pause-DR

No specific function is performed in the stable Pause-DR state, in which the TAP controller can remain indefinitely. The Pause-DR state provides the capability of suspending and resuming data register scan operations without loss of data.

Update-DR

If the current instruction calls for the selected data register to be updated with current data, such update occurs on the falling edge of TCK following entry to the Update-DR state.

Capture-IR

When an instruction register scan is selected, the T AP controller must pass through the Capture-IR state. In the Capture-IR state, the instruction register captures its current status value. This capture operation occurs on the rising edge of TCK upon which the TAP controller exits the Capture-IR state.

For the ′ABT18502, the status value loaded in the Capture-IR state is the fixed binary value 10000001.

Shift-IR

Upon entry to the Shift-IR state, the instruction register is placed in the scan path between TDI and TDO and, on the first falling edge of TCK, TDO goes from the high-impedance state to an active state. TDO enables to the logic level present in the least significant bit of the instruction register.

While in the stable Shift-IR state, instruction data is serially shifted through the instruction register on each TCK cycle. The first shift occurs on the first rising edge of TCK after entry to the Shift-IR state (i.e., no shifting occurs during the TCK cycle in which the TAP controller changes from Capture-IR to Shift-IR or from Exit2-IR to Shift-IR). The last shift occurs on the rising edge of TCK upon which the T AP controller exits the Shift-IR state.

Exit1-IR, Exit2-IR

The Exit1-IR and Exit2-IR states are temporary states used to end an instruction register scan. It is possible to return to the Shift-IR state from either Exit1-IR or Exit2-IR without recapturing the instruction register.

On the first falling edge of TCK after entry to Exit1-IR, TDO goes from the active state to the high-impedance state.

8 8

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 9

SN54ABT18502, SN74ABT18502

SCAN TEST DEVICES WITH

18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

state diagram description (continued)

Pause-IR

No specific function is performed in the stable Pause-IR state, in which the T AP controller can remain indefinitely. The Pause-IR state provides the capability of suspending and resuming instruction register scan operations without loss of data.

Update-IR

The current instruction is updated and takes effect on the falling edge of TCK following entry to the Update-IR state.

With the exception of the bypass and device identification registers, any test register can be thought of as a serial shift register with a shadow latch on each bit. The bypass and device identification registers differ in that they contain only a shift register. During the appropriate capture state (Capture-IR for instruction register, Capture-DR for data registers), the shift register may be parallel loaded from a source specified by the current instruction. During the appropriate shift state (Shift-IR or Shift-DR), the contents of the shift register are shifted out from TDO while new contents are shifted in at TDI. During the appropriate update state (Update-IR or Update-DR), the shadow latches are updated from the shift register.

instruction register description

The instruction register (IR) is eight bits long and is used to tell the device what instruction is to be executed. Information contained in the instruction includes the mode of operation (either normal mode, in which the device performs its normal logic function, or test mode, in which the normal logic function is inhibited or altered), the test operation to be performed, which of the four data registers is to be selected for inclusion in the scan path during data register scans, and the source of data to be captured into the selected data register during Capture-DR.

Table 4 lists the instructions supported by the ′ABT18502. The even-parity feature specified for SCOPE  devices is supported in this device. Bit 7 of the instruction opcode is the parity bit. Any instructions that are defined for SCOPE devices but are not supported by this device default to BYPASS.

During Capture-IR, the IR captures the binary value 10000001. As an instruction is shifted in, this value will be shifted out via TDO and can be inspected as verification that the IR is in the scan path. During Update-IR, the value that has been shifted into the IR is loaded into shadow latches. At this time, the current instruction is updated and any specified mode change takes effect. At power up or in the Test-Logic-Reset state, the IR is reset to the binary value 10000001, which selects the IDCODE instruction.

The instruction register order of scan is illustrated in Figure 2.

Bit 7 Parity (MSB)

Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1

Figure 2. Instruction Register Order of Scan

Bit 0

(LSB)

TDOTDI

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 10

SN54ABT18502, SN74ABT18502 SCAN TEST DEVICES WITH 18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

data register description

boundary-scan register

The boundary-scan register (BSR) is 84 bits long. It contains one boundary-scan cell (BSC) for each normal-function input pin and two BSCs for each normal-function I/O pin (one for input data and one for output data). The BSR is used 1) to store test data that is to be applied internally to the inputs of the normal on-chip logic and/or externally to the device output pins, and/or 2) to capture data that appears internally at the outputs of the normal on-chip logic and/or externally at the device input pins.

The source of data to be captured into the BSR during Capture-DR is determined by the current instruction. The contents of the BSR can change during Run-Test/Idle as determined by the current instruction. At power up or in Test-Logic-Reset, the value of each BSC is reset to logic 0 except BSCs 83–80, which are reset to logic 1.

The boundary-scan register order of scan is from TDI through bits 83–0 to TDO. Table 1 shows the boundary-scan register bits and their associated device pin signals.

Table 1. Boundary-Scan Register Configuration

BSR BIT

NUMBER

83 2OEAB 71 2A9-I 53 2A9-O 35 2B9-I 17 2B9-O 82 1OEAB 70 2A8-I 52 2A8-O 34 2B8-I 16 2B8-O 81 2OEBA 69 2A7-I 51 2A7-O 33 2B7-I 15 2B7-O 80 1OEBA 68 2A6-I 50 2A6-O 32 2B6-I 14 2B6-O 79 2CLKAB 67 2A5-I 49 2A5-O 31 2B5-I 13 2B5-O 78 1CLKAB 66 2A4-I 48 2A4-O 30 2B4-I 12 2B4-O 77 2CLKBA 65 2A3-I 47 2A3-O 29 2B3-I 11 2B3-O 76 1CLKBA 64 2A2-I 46 2A2-O 28 2B2-I 10 2B2-O 75 2LEAB 63 2A1-I 45 2A1-O 27 2B1-I 9 2B1-O 74 1LEAB 62 1A9-I 44 1A9-O 26 1B9-I 8 1B9-O 73 2LEBA 61 1A8-I 43 1A8-O 25 1B8-I 7 1B8-O 72 1LEBA 60 1A7-I 42 1A7-O 24 1B7-I 6 1B7-O –– –– 59 1A6-I 41 1A6-O 23 1B6-I 5 1B6-O –– –– 58 1A5-I 40 1A5-O 22 1B5-I 4 1B5-O –– –– 57 1A4-I 39 1A4-O 21 1B4-I 3 1B4-O –– –– 56 1A3-I 38 1A3-O 20 1B3-I 2 1B3-O –– –– 55 1A2-I 37 1A2-O 19 1B2-I 1 1B2-O –– –– 54 1A1-I 36 1A1-O 18 1B1-I 0 1B1-O

DEVICE

SIGNAL

boundary-control register

BSR BIT

NUMBER

DEVICE

SIGNAL

BSR BIT

NUMBER

DEVICE

SIGNAL

BSR BIT

NUMBER

DEVICE

SIGNAL

BSR BIT

NUMBER

DEVICE

SIGNAL

The boundary-control register (BCR) is 21 bits long. The BCR is used in the context of the RUNT instruction to implement additional test operations not included in the basic SCOPE instruction set. Such operations include pseudo-random pattern generation (PRPG), parallel signature analysis (PSA) with input masking, and binary count up (COUNT). Table 5 shows the test operations that are decoded by the BCR.

During Capture-DR, the contents of the BCR are not changed. At power up or in Test-Logic-Reset, the BCR is reset to the binary value 000000000000000000010, which selects the PSA test operation with no input masking.

10 10

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 11

SN54ABT18502, SN74ABT18502

SCAN TEST DEVICES WITH

18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

data register description (continued)

The boundary-control register order of scan is from TDI through bits 20–0 to TDO. Table 2 shows the boundary-control register bits and their associated test control signals.

Table 2. Boundary Control Register Configuration

BCR BIT

NUMBER

20 MASK2.9 11 MASK1.9 2 OPCODE2 19 MASK2.8 10 MASK1.8 1 OPCODE1 18 MASK2.7 9 MASK1.7 0 OPCODE0 17 MASK2.6 8 MASK1.6 –– –– 16 MASK2.5 7 MASK1.5 –– –– 15 MASK2.4 6 MASK1.4 –– –– 14 MASK2.3 5 MASK1.3 –– –– 13 MASK2.2 4 MASK1.2 –– –– 12 MASK2.1 3 MASK1.1 –– ––

TEST

CONTROL

SIGNAL

BCR BIT

NUMBER

TEST

CONTROL

SIGNAL

BCR BIT

NUMBER

TEST

CONTROL

SIGNAL

bypass register

The bypass register is a one-bit scan path that can be selected to shorten the length of the system scan path, thereby reducing the number of bits per test pattern that must be applied to complete a test operation.

During Capture-DR, the bypass register captures a logic 0. The bypass register order of scan is illustrated in Figure 3.

Bit 0

TDOTDI

Figure 3. Bypass Register Order of Scan

device identification register

The device identification register (IDR) is 32 bits long. It can be selected and read to identify the manufacturer, part number, and version of this device.

During Capture-DR, the binary value 00000000000000000110000000101111 (0000602F, hex) is captured in the device identification register to identify this device as Texas Instruments SN54/74ABT18502, version 0.

The device identification register order of scan is from TDO through bits 31–0 to TDO. T able 3 shows the device identification register bits and their significance.

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 12

SN54ABT18502, SN74ABT18502 SCAN TEST DEVICES WITH 18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

Table 3. Device Identification Register Configuration

IDR BIT

NUMBER

31 VERSION3 27 PARTNUMBER15 11 MANUFACTURER10 30 VERSION2 26 PARTNUMBER14 10 MANUFACTURER09 29 VERSION1 25 PARTNUMBER13 9 MANUFACTURER08 28 VERSION0 24 PARTNUMBER12 8 MANUFACTURER07 –– –– 23 PARTNUMBER11 7 MANUFACTURER06 –– –– 22 PARTNUMBER10 6 MANUFACTURER05 –– –– 21 PARTNUMBER09 5 MANUFACTURER04 –– –– 20 PARTNUMBER08 4 MANUFACTURER03 –– –– 19 PARTNUMBER07 3 MANUFACTURER02 –– –– 18 PARTNUMBER06 2 MANUFACTURER01 –– –– 17 PARTNUMBER05 1 MANUFACTURER00 –– –– 16 PARTNUMBER04 0 LOGIC1 –– –– 15 PARTNUMBER03 –– –– –– –– 14 PARTNUMBER02 –– –– –– –– 13 PARTNUMBER01 –– –– –– –– 12 PARTNUMBER00 –– ––

†

Note that for TI products, bits 11–0 of the device identification register always contains the binary value 00000010111 1 (02F , hex).

IDENTIFICATION

SIGNIFICANCE

IDR BIT

NUMBER

IDENTIFICATION

SIGNIFICANCE

IDR BIT

NUMBER

IDENTIFICATION

SIGNIFICANCE

†

Table 4. Instruction Register Opcodes

BINARY CODE

BIT 7 → BIT 0

MSB → LSB

00000000 EXTEST Boundary scan Boundary scan Test 10000001 IDCODE Identification read Device identification Normal 10000010 SAMPLE/PRELOAD Sample boundary Boundary scan Normal 0000001 1 INTEST Boundary scan Boundary scan Test 10000100 BYPASS 00000101 BYPASS 00000110 HIGHZ Control boundary to high impedance Bypass Modified test 100001 11 CLAMP Control boundary to 1/0 Bypass Test 10001000 BYPASS 00001001 RUNT Boundary run test Bypass Test 00001010 READBN Boundary read Boundary scan Normal 1000101 1 READBT Boundary read Boundary scan T est 00001 100 CELLTST Boundary self test Boundary scan Normal 10001 101 T OPHIP Boundary toggle outputs Bypass Test 10001 110 SCANCN Boundary-control register scan Boundary control Normal

00001 111 SCANCT Boundary-control register scan Boundary control Test All others BYPASS Bypass scan Bypass Normal

†

Bit 7 is used to maintain even parity in the 8-bit instruction.

‡

The BYPASS instruction is executed in lieu of a SCOPE instruction that is not supported in the ′ABT18502.

†

SCOPE OPCODE DESCRIPTION

‡ ‡

‡

SELECTED DATA

Bypass scan Bypass Normal Bypass scan Bypass Normal

Bypass scan Bypass Normal

† † † † † † † † † † †

MODE

12 12

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 13

SN54ABT18502, SN74ABT18502

SCAN TEST DEVICES WITH

18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

instruction register opcode description

The instruction register opcodes are shown in Table 4. The following descriptions detail the operation of each instruction.

boundary scan

This instruction conforms to the IEEE Standard 1149.1-1990 EXTEST and INTEST instructions. The boundary-scan register is selected in the scan path. Data appearing at the device input pins is captured in the input BSCs, while data appearing at the outputs of the normal on-chip logic is captured in the output BSCs. Data scanned into the input BSCs is applied to the inputs of the normal on-chip logic, while data scanned into the output BSCs is applied to the device output pins. The device operates in the test mode.

bypass scan

This instruction conforms to the IEEE Standard 1149.1-1990 BYPASS instruction. The bypass register is selected in the scan path. A logic 0 value is captured in the bypass register during Capture-DR. The device operates in the normal mode.

sample boundary

This instruction conforms to the IEEE Standard 1149.1-1990 SAMPLE/PRELOAD instruction. The boundary-scan register is selected in the scan path. Data appearing at the device input pins is captured in the input BSCs, while data appearing at the outputs of the normal on-chip logic is captured in the output BSCs. The device operates in the normal mode.

control boundary to high impedance

This instruction conforms to the IEEE P1 149.1A HIGHZ instruction. The bypass register is selected in the scan path. A logic 0 value is captured in the bypass register during Capture-DR. The device operates in a modified test mode in which all device I/O pins are placed in the high-impedance state, the device input pins remain operational, and the normal on-chip logic function is performed.

control boundary to 1/0

This instruction conforms to the IEEE P1 149.1A CLAMP instruction. The bypass register is selected in the scan path. A logic 0 value is captured in the bypass register during Capture-DR. Data in the input BSCs is applied to the inputs of the normal on-chip logic, while data in the output BSCs is applied to the device output pins. The device operates in the test mode.

boundary run test

The bypass register is selected in the scan path. A logic 0 value is captured in the bypass register during Capture-DR. The device operates in the test mode. The test operation specified in the boundary-control register is executed during Run-T est/Idle. The five test operations decoded by the boundary-control register are: sample inputs/toggle outputs (TOPSIP), pseudo-random pattern generation (PRPG), parallel signature analysis (PSA), simultaneous PSA and PRPG (PSA/PRPG), and simultaneous PSA and binary count up (PSA/COUNT).

boundary read

The boundary-scan register is selected in the scan path. The value in the boundary-scan register remains unchanged during Capture-DR. This instruction is useful for inspecting data after a PSA operation.

boundary self test

The boundary-scan register is selected in the scan path. All BSCs capture the inverse of their current values during Capture-DR. In this way , the contents of the shadow latches can be read out to verify the integrity of both shift register and shadow latch elements of the boundary-scan register. The device operates in the normal mode.

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 14

SN54ABT18502, SN74ABT18502 SCAN TEST DEVICES WITH 18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

instruction register opcode description (continued)

boundary toggle outputs

The bypass register is selected in the scan path. A logic 0 value is captured in the bypass register during Capture-DR. Data in the shift-register elements of the selected output BSCs is toggled on each rising edge of TCK in Run-T est/Idle, updated in the shadow latches, and applied to the associated device output pins on each falling edge of TCK in Run-Test/Idle. Data in the selected input BSCs remains constant and is applied to the inputs of the normal on-chip logic. Data appearing at the device input pins is not captured in the input BSCs. The device operates in the test mode.

boundary-control register scan

The boundary-control register is selected in the scan path. The value in the boundary-control register remains unchanged during Capture-DR. This operation must be performed prior to a boundary run test operation in order to specify which test operation is to be executed.

Table 5. Boundary-Control Register Opcodes

BINARY CODE

BIT 2 → BIT 0

MSB → LSB

X00 Sample inputs/toggle outputs (TOPSIP) X01 Pseudo-random pattern generation/36-bit mode (PRPG) X10 Parallel signature analysis/36-bit mode (PSA)

011 Simultaneous PSA and PRPG/18-bit mode (PSA/PRPG) 111 Simultaneous PSA and binary count up/18-bit mode (PSA/COUNT)

DESCRIPTION

boundary-control register opcode description

The boundary-control register opcodes are decoded from BCR bits 2–0 as shown in T able 5. The selected test operation is performed while the RUNT instruction is executed in the Run-Test/Idle state. The following descriptions detail the operation of each BCR instruction and illustrate the associated PSA and PRPG algorithms.

In general, while the control input BSCs (bits 83–72) are not included in the toggle, PSA, PRPG, or COUNT algorithms, the output-enable BSCs (bits 83–80 of the BSR) control the drive state (active or high-impedance) of the selected device output pins. These BCR instructions are only valid when both bytes of the device are operating in one direction of data flow (that is, 1OEAB of data flow (that is, 1OEAB = 2OEAB and 1OEBA = 2OEBA). Otherwise, the bypass instruction is operated.

PSA input masking

Bits 20 – 3 of the boundary-control register are used to specify device input pins to be masked from PSA operations. Bit 20 selects masking for device input pin 2A9 during A-to-B data flow or for device input pin 2B9 during B-to-A data flow. Bit 3 selects masking for device input pins 1A1 or 1B1 during A-to-B or B-to-A data flow , respectively . Bits intermediate to 20 and 3 mask corresponding device input pins in order from most significant to least significant, as indicated in Table 2. When the mask bit which corresponds to a particular device input has a logic 1 value, the device input pin is masked from any PSA operation, meaning that the state of the device input pin is ignored and has no effect on the generated signature. Otherwise, when a mask bit has a logic 0 value, the corresponding device input is not masked from the PSA operation.

≠1OEBA and 2OEAB ≠2OEBA) and in the same direction

14 14

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 15

SN54ABT18502, SN74ABT18502

SCAN TEST DEVICES WITH

18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

boundary-control register opcode description (continued)

sample inputs/toggle outputs (TOPSIP)

Data appearing at the selected device input pins is captured in the shift-register elements of the selected BSCs on each rising edge of TCK. This data is then updated in the shadow latches of the selected input BSCs and applied to the inputs of the normal on-chip logic. Data in the shift-register elements of the selected output BSCs is toggled on each rising edge of TCK and is then updated in the shadow latches and applied to the associated device output pins on each falling edge of TCK.

pseudo-random pattern generation (PRPG)

A pseudo-random pattern is generated in the shift-register elements of the selected BSCs on each rising edge of TCK, updated in the shadow latches, and applied to the associated device output pins on each falling edge of TCK. This data is also updated in the shadow latches of the selected input BSCs and applied to the inputs of the normal on-chip logic. Figures 4 and 5 illustrate the 36-bit linear-feedback shift-register algorithms through which the patterns are generated. An initial seed value should be scanned into the boundary-scan register prior to performing this operation. A seed value of all zeroes will not produce additional patterns.

2A7-I 2A6-I 2A5-I 2A4-I 2A3-I 2A2-I 2A1-I2A8-I2A9-I

1A7-I 1A6-I 1A5-I 1A4-I 1A3-I 1A2-I 1A1-I1A8-I1A9-I

2B8-O 2B7-O 2B6-O 2B5-O 2B4-O 2B3-O 2B2-O 2B1-O2B9-O

1B8-O 1B7-O 1B6-O 1B5-O 1B4-O 1B3-O 1B2-O 1B1-O1B9-O

Figure 4. 36-Bit PRPG Configuration (1OEAB = 2OEAB = 0, 1OEBA = 2OEBA = 1)

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 16

SN54ABT18502, SN74ABT18502 SCAN TEST DEVICES WITH 18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

2B7-I 2B6-I 2B5-I 2B4-I 2B3-I 2B2-I 2B1-I2B8-I2B9-I

1B7-I 1B6-I 1B5-I 1B4-I 1B3-I 1B2-I 1B1-I1B8-I1B9-I

2A8-O 2A7-O 2A6-O 2A5-O 2A4-O 2A3-O 2A2-O 2A1-O2A9-O

1A8-O 1A7-O 1A6-O 1A5-O 1A4-O 1A3-O 1A2-O 1A1-O1A9-O

Figure 5. 36-Bit PRPG Configuration (1OEAB = 2OEAB = 1, 1OEBA = 2OEBA = 0)

16 16

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 17

SN54ABT18502, SN74ABT18502

SCAN TEST DEVICES WITH

18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

boundary-control register opcode description (continued)

parallel signature analysis (PSA)

Data appearing at the selected device input pins is compressed into a 36-bit parallel signature in the shift-register elements of the selected BSCs on each rising edge of TCK. This data is updated in the shadow latches of the selected input BSCs and applied to the inputs of the normal on-chip logic. Data in the shadow latches of the selected output BSCs remains constant and is applied to the device outputs. Figures 6 and 7 illustrate the 36-bit linear-feedback shift-register algorithms through which the signature is generated. An initial seed value should be scanned into the boundary-scan register prior to performing this operation.

2A7-I 2A6-I 2A5-I 2A4-I 2A3-I 2A2-I 2A1-I2A8-I2A9-I

1A7-I 1A6-I 1A5-I 1A4-I 1A3-I 1A2-I 1A1-I1A8-I1A9-I

MASKX.X

2B8-O 2B7-O 2B6-O 2B5-O 2B4-O 2B3-O 2B2-O 2B1-O2B9-O

1B8-O 1B7-O 1B6-O 1B5-O 1B4-O 1B3-O 1B2-O 1B1-O1B9-O

Figure 6. 36-Bit PSA Configuration (1OEAB = 2OEAB = 0, 1OEBA = 2OEBA = 1)

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 18

SN54ABT18502, SN74ABT18502 SCAN TEST DEVICES WITH 18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

2B7-I 2B6-I 2B5-I 2B4-I 2B3-I 2B2-I 2B1-I2B8-I2B9-I

1B7-I 1B6-I 1B5-I 1B4-I 1B3-I 1B2-I 1B1-I1B8-I1B9-I

MASKX.X

2A8-O 2A7-O 2A6-O 2A5-O 2A4-O 2A3-O 2A2-O 2A1-O2A9-O

1A8-O 1A7-O 1A6-O 1A5-O 1A4-O 1A3-O 1A2-O 1A1-O1A9-O

Figure 7. 36-Bit PSA Configuration (1OEAB = 2OEAB = 1, 1OEBA = 2OEBA = 0)

18 18

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 19

SN54ABT18502, SN74ABT18502

SCAN TEST DEVICES WITH

18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

boundary-control register opcode description (continued)

simultaneous PSA and PRPG (PSA/PRPG)

Data appearing at the selected device input pins is compressed into an 18-bit parallel signature in the shift-register elements of the selected input BSCs on each rising edge of TCK. This data is updated in the shadow latches of the selected input BSCs and applied to the inputs of the normal on-chip logic. At the same time, an 18-bit pseudo-random pattern is generated in the shift-register elements of the selected output BSCs on each rising edge of TCK, updated in the shadow latches, and applied to the associated device output pins on each falling edge of TCK. Figures 8 and 9 illustrate the 18-bit linear-feedback shift-register algorithms through which the signature and patterns are generated. An initial seed value should be scanned into the boundary-scan register prior to performing this operation. A seed value of all zeroes will not produce additional patterns.

2A7-I 2A6-I 2A5-I 2A4-I 2A3-I 2A2-I 2A1-I2A8-I2A9-I

1A7-I 1A6-I 1A5-I 1A4-I 1A3-I 1A2-I 1A1-I1A8-I1A9-I

MASKX.X

2B8-O 2B7-O 2B6-O 2B5-O 2B4-O 2B3-O 2B2-O 2B1-O2B9-O

1B8-O 1B7-O 1B6-O 1B5-O 1B4-O 1B3-O 1B2-O 1B1-O1B9-O

Figure 8. 18-Bit PSA/PRPG Configuration (1OEAB = 2OEAB = 0, 1OEBA = 2OEBA = 1)

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 20

SN54ABT18502, SN74ABT18502 SCAN TEST DEVICES WITH 18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

2B7-I 2B6-I 2B5-I 2B4-I 2B3-I 2B2-I 2B1-I2B8-I2B9-I

1B7-I 1B6-I 1B5-I 1B4-I 1B3-I 1B2-I 1B1-I1B8-I1B9-I

MASKX.X

2A8-O 2A7-O 2A6-O 2A5-O 2A4-O 2A3-O 2A2-O 2A1-O2A9-O

1A8-O 1A7-O 1A6-O 1A5-O 1A4-O 1A3-O 1A2-O 1A1-O1A9-O

Figure 9. 18-Bit PSA/PRPG Configuration (1OEAB = 2OEAB = 1, 1OEBA = 2OEBA = 0)

20 20

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 21

SN54ABT18502, SN74ABT18502

SCAN TEST DEVICES WITH

18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

boundary-control register opcode description (continued)

simultaneous PSA and binary count up (PSA/COUNT)

Data appearing at the selected device input pins is compressed into an 18-bit parallel signature in the shift-register elements of the selected input BSCs on each rising edge of TCK. This data is updated in the shadow latches of the selected input BSCs andapplied to the inputs of the normal on-chip logic. At the same time, an 18-bit binary count-up pattern is generated in the shift-register elements of the selected output BSCs on each rising edge of TCK, updated in the shadow latches, and applied to the associated device output pins on each falling edge of TCK. Figures 10 and 11 illustrate the 18-bit linear-feedback shift–register algorithms through which the signature is generated. An initial seed value should be scanned into the boundary-scan register prior to performing this operation.

2A7-I 2A6-I 2A5-I 2A4-I 2A3-I 2A2-I 2A1-I2A8-I2A9-I

1A7-I 1A6-I 1A5-I 1A4-I 1A3-I 1A2-I 1A1-I1A8-I1A9-I

MSB

MASKX.X

2B8-O 2B7-O 2B6-O 2B5-O 2B4-O 2B3-O 2B2-O 2B1-O2B9-O

LSB

1B8-O 1B7-O 1B6-O 1B5-O 1B4-O 1B3-O 1B2-O 1B1-O1B9-O

Figure 10. 18-Bit PSA/COUNT Configuration (1OEAB = 2OEAB = 0, 1OEBA = 2OEBA = 1)

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 22

SN54ABT18502, SN74ABT18502 SCAN TEST DEVICES WITH 18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

2B7-I 2B6-I 2B5-I 2B4-I 2B3-I 2B2-I 2B1-I2B8-I2B9-I

1B9-I

MSB

MASKX.X

2A8-O 2A7-O 2A6-O 2A5-O 2A4-O 2A3-O 2A2-O 2A1-O2A9-O

1A8-O 1A7-O 1A6-O 1A5-O 1A4-O 1A3-O 1A2-O 1A1-O1A9-O

1B7-I 1B6-I 1B5-I 1B4-I 1B3-I 1B2-I 1B1-I1B8-I

LSB

Figure 11. 18-Bit PSA/COUNT Configuration (1OEAB = 2OEAB = 1, 1OEBA = 2OEBA = 0)

22 22

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 23

SN54ABT18502, SN74ABT18502

SCAN TEST DEVICES WITH

18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

timing description

All test operations of the ′ABT18502 are synchronous to the test clock (TCK). Data on the TDI, TMS, and normal-function inputs is captured on the rising edge of TCK. Data appears on the TDO and normal-function output pins on the falling edge of TCK. The TAP controller is advanced through its states (as illustrated in Figure 1) by changing the value of TMS on the falling edge of TCK and then applying a rising edge to TCK.

A simple timing example is illustrated in Figure 12. In this example, the TAP controller begins in the T est-Logic-Reset state and is advanced through its states as necessary to perform one instruction register scan and one data register scan. While in the Shift-IR and Shift-DR states, TDI is used to input serial data, and TDO is used to output serial data. The T AP controller is then returned to the T est-Logic-Reset state. Table 6 explains the operation of the test circuitry during each TCK cycle.

Table 6. Explanation of Timing Example

TCK

CYCLE(S)

1 Test-Logic-Reset 2 Run-Test/Idle

3 Select-DR-Scan 4 Select-IR-Scan

5 Capture-IR

6 Shift-IR

7–13 Shift-IR

14 Exit1-IR TDO becomes inactive (goes to the high-impedance state) on the falling edge of TCK. 15 Update-IR The IR is updated with the new instruction (BYPASS) on the falling edge of TCK. 16 Select-DR-Scan

17 Capture-DR

18 Shift-DR

19–20 Shift-DR The binary value 101 is shifted in via TDI, while the binary value 010 is shifted out via TDO.

21 Exit1-DR TDO becomes inactive (goes to the high-impedance state) on the falling edge of TCK. 22 Update-DR In general, the selected data register is updated with the new data on the falling edge of TCK. 23 Select-DR-Scan 24 Select-IR-Scan 25 Test-Logic-Reset Test operation completed

TAP STATE

AFTER TCK

DESCRIPTION

TMS is changed to a logic 0 value on the falling edge of TCK to begin advancing the TAP controller toward the desired state.

The IR captures the 8-bit binary value 10000001 on the rising edge of TCK as the TAP controller exits the Capture-IR state.

TDO becomes active and TDI is made valid on the falling edge of TCK. The first bit is shifted into the TAP on the rising edge of TCK as the TAP controller advances to the next state.

One bit is shifted into the IR on each TCK rising edge. With TDI held at a logic 1 value, the 8-bit binary value 11111111 is serially scanned into the IR. At the same time, the 8-bit binary value 10000001 is serially scanned out of the IR via TDO. In TCK cycle 13, TMS is changed to a logic 1 value to end the instruction register scan on the next TCK cycle. The last bit of the instruction is shifted as the TAP controller advances from Shift-IR to Exit1-IR.

The bypass register captures a logic 0 value on the rising edge of TCK as the TAP controller exits the Capture-DR state.

TDO becomes active and TDI is made valid on the falling edge of TCK. The first bit is shifted into the TAP on the rising edge of TCK as the TAP controller advances to the next state.

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 24

SN54ABT18502, SN74ABT18502

ООООО

SCAN TEST DEVICES WITH 18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

TCK

TMS

TDI

TDO

TAP

Controller

State

Run-Test/Idle

Test-Logic-Reset

Select-DR-Scan

Capture-IR

Select-IR-Scan

Shift-IR

3-State (TDO) or Don’t Care (TDI)

Exit1-IR

Update-IR

Capture-DR

Select-DR-Scan

Shift-DR

Exit1-DR

Update-DR

Select-IR-Scan

Select-DR-Scan

Figure 12. Timing Example

absolute maximum ratings over operating free-air temperature range (unless otherwise noted)

Supply voltage range, VCC –0.5 V to 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Input voltage range, VI (except I/O ports) (see Note 1) –0.5 V to 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Input voltage range, VI (I/O ports) (see Note 1) –0.5 V to 5.5 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Voltage range applied to any output in the high state or power-off state, V

Current into any output in the low state, IO: SN54ABT18502 96 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SN74ABT18502 128 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Input clamp current, I Output clamp current, I Continuous current through V

< 0) –18 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

< 0) –50 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

576 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Continuous current through GND 1152 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maximum power dissipation at TA = 55°C (in still air) (see Note 2) 885 mW. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Storage temperature range –65°C to 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

†

Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

NOTES: 1. The input and output negative-voltage ratings can be exceeded if the input and output clamp-current ratings are observed.

2. For the SN74ABT18502 (PM package), the power derating factor for ambient temperatures greater than 55°C is –10.5 mW/°C.

–0.5 V to 5.5 V. . . . . . . . . . . . .

Test-Logic-Reset

†

24 24

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 25

SN54ABT18502, SN74ABT18502

UNIT

SCAN TEST DEVICES WITH

18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

recommended operating conditions (see Note 3)

SN54ABT18502 SN74ABT18502

MIN MAX MIN MAX

V V V V I

∆t/∆v Input transition rise or fall rate 10 10 ns/V T

NOTE 3: Unused or floating pins (input or I/O) must be held high or low.

Supply voltage 4.5 5.5 4.5 5.5 V

High-level input voltage 2 2 V

Low-level input voltage 0.8 0.8 V

Input voltage 0 V

High-level output current –24 –32 mA Low-level output current 48 64 mA

Operating free-air temperature –55 125 –40 85 °C

0 V

PRODUCT PREVIEW information concerns products in the formative or design phase of development. Characteristic data and other specifications are design goals. Texas Instruments reserves the right to change or discontinue these products without notice.

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 26

SN54ABT18502, SN74ABT18502

PARAMETER

TEST CONDITIONS

UNIT

5.5 V,

orts

∆I

505050µA

SCAN TEST DEVICES WITH 18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

electrical characteristics over recommended operating free-air temperature range (unless otherwise noted)

TA = 25°C SN54ABT18502 SN74ABT18502

MIN TYP†MAX MIN MAX MIN MAX

OZH

OZL

OZPU

OZPD

off

CEX

†

All typical values are at VCC = 5 V.

‡

On products compliant to MIL-STD-883, Class B, this parameter does not apply.

The parameters I

Not more than one output should be tested at a time, and the duration of the test should not exceed one second.

This is the increase in supply current for each input that is at the specified TTL voltage level rather than VCC or GND.

VCC = 4.5 V, II = –18 mA –1.2 –1.2 –1.2 V VCC = 4.5 V, IOH = – 3 mA 2.5 2.5 2.5 VCC = 5 V, IOH = – 3 mA 3 3 3 VCC = 4.5 V, IOH = – 24 mA 2 2 VCC = 4.5 V, IOH = – 32 mA 2

= 4.5

= 5.5 V,

VI = VCC or GND VCC = 5.5 V,

VI = V

VCC = 5.5 V, VI = GND

VCC = 5.5 V, VO = 2.7 V 50 50 50 µA

VCC = 5.5 V, VO = 0.5 V –50 –50 –50 µA VCC = 0 to 2 V,

VO = 2.7 V or 0.5 V VCC = 2 V to 0,

VO = 2.7 V or 0.5 V VCC = 0, VI or VO ≤ 4.5 V ±100 ±450 ±100 µA VCC = 5.5 V,

VO = 5.5 V VCC = 5.5 V, VO = 2.5 V –50 –110 –200 –50 –200 –50 –200 mA

= 5.5 V IO = 0, VI = VCC or GND

= 5.5 V, One input at 3.4 V, Other inputs at VCC or GND

VI = 2.5 V or 0.5 V Control inputs 3 pF VO = 2.5 V or 0.5 V A or B ports 10 pF VO = 2.5 V or 0.5 V TDO 8 pF

and I

OZH

OZL

IOL = 48 mA 0.55 0.55 IOL = 64 mA 0.55

CLK,LE,OE,TCK ±1 ±1 ±1 A or B ports ±100 ±100 ±100

TDI, TMS 10 10 10 µA

TDI, TMS –150 –150 –150 µA

OE = 0.8 V

Outputs high 50 50 50 µA

A or B p

include the input leakage current.

Outputs high 3.5 5.5 5.5 5.5 Outputs low 33 38 38 38 mA Outputs disabled 2.9 5 5 5

‡

±50 ±50 ±50 µA

0.55

26 26

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 27

SN54ABT18502, SN74ABT18502

UNIT

twPulse duration

A bef

LEAB↓

LEBA↓

thHold time

UNIT

SCAN TEST DEVICES WITH

18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

timing requirements over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted) (normal mode) (see Figure 13)

SN54ABT18502 SN74ABT18502

MIN MAX MIN MAX

clock

timing requirements over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted) (test mode) (see Figure 13)123

clock

Clock frequency CLKAB or CLKBA 0 100 0 100 MHz

CLKAB or CLKBA high or low 3.5 3.5 LEAB or LEBA high 3.5 3.5 A before CLKAB↑ or B before CLKBA↑ 4 4

Setup time

Clock frequency TCK 0 50 0 50 MHz Pulse duration TCK high or low 8 8 ns

Setup time

Hold time

Delay time Power up to TCK↑ 50 50 ns Rise time VCC power up 1 1 µs

ore

A after CLKAB↑ or B after CLKBA↑ 0 0 A after LEAB↓ or B after LEBA↓ 2 2

or B before

A, B, CLK, LE, or OE before TCK↑ 4.5 4.5 TDI before TCK↑ TMS before TCK↑ 3 3 A, B, CLK, LE, or OE after TCK↑ 0.5 0.5 TDI after TCK↑ TMS after TCK↑ 0.5 0.5

CLK high 3.5 3.5 CLK low 2 2

SN54ABT18502 SN74ABT18502

MIN MAX MIN MAX

7.5 7.5

0.5 0.5

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 28

SN54ABT18502, SN74ABT18502

(INPUT)

(OUTPUT)

A or B

B or A

CLKAB or CLKBA

B or A

LEAB or LEBA

B or A

OEAB

OEBA

B or A

OEAB or OEBA

B or A

(INPUT)

(OUTPUT)

TCK↓

A or B

TCK↓

TDO

TCK↓

A or B

TCK↓

TDO

TCK↓

A or B

TCK↓

TDO

SCAN TEST DEVICES WITH 18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

switching characteristics over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted) (normal mode) (see Figure 13)

VCC = 5 V,

TA = 25°C

MIN TYP MAX MIN MAX MIN MAX

2 3.8 5.6 2 6.5 2 6 2 3.8 5.6 2 7.2 2 6

2.5 4.7 5.7 2.5 7.2 2.5 6

2.5 4.7 5.7 2.5 7.1 2.5 6

2.5 4.9 6.4 2.5 7.5 2.5 7

2.5 4.9 6.5 2.5 7.8 2.5 7 2 4.9 6.3 2 7.5 2 7

2.5 5.6 7.2 2.5 8.3 2.5 8 3 6.1 7.8 3 9.6 3 8.8

2.5 4.8 6.5 2.5 7.4 2.5 7.3

PARAMETER

max

PLH

PHL

PLH

PHL

PLH

PHL

PZH

PZL

PHZ

PLZ

FROM

CLKAB or CLKBA 100 130 100 100 MHz

switching characteristics over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted) (test mode) (see Figure 13)12345

VCC = 5 V,

TA = 25°C

MIN TYP MAX MIN MAX MIN MAX

2.5 9.1 11.4 2.5 14.4 2.5 13.5

2.5 9.1 10.8 2.5 13.6 2.5 12.4 2 3.8 5.1 2 6 2 5.6 2 3.8 5.3 2 6.6 2 6

4.5 9.5 11.5 4.5 14.2 4.5 13.4 5 10.1 12.2 5 14.8 5 14

2.5 4.6 5.9 2.5 7.2 2.5 6.8 3 5.2 6.8 3 7.9 3 7.5 4 11.6 14.3 4 17.5 4 16.3

3.5 11.1 13.6 3.5 16.7 3.5 15.3 3 5.3 7.2 3 7.7 3 7.6 3 5.2 6.8 3 8 3 7.6

PARAMETER

max

PLH

PHL

PLH

PHL

PZH

PZL

PZH

PZL

PHZ

PLZ

PHZ

PLZ

FROM

TCK 50 90 50 50 MHz

SN54ABT18502 SN74ABT18502

UNIT

28 28

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 29

From Output

Under Test

CL = 50 pF

(see Note A)

Input

PARAMETER MEASUREMENT INFORMATION

500 Ω

LOAD CIRCUIT FOR OUTPUTS

1.5 V 1.5 V

VOLTAGE WAVEFORMS

PULSE DURATION

7 V

Open

GND

3 V

0 V

SN54ABT18502, SN74ABT18502

SCAN TEST DEVICES WITH

18-BIT REGISTERED BUS TRANSCEIVERS

SCBS109B – AUGUST 1992 – REVISED JUNE 1993

TEST S1

Timing Input

Data Input

PLH/tPHL

PLZ/tPZL

PHZ/tPZH

1.5 V 1.5 V

VOLTAGE WAVEFORMS

SETUP AND HOLD TIMES

Open

1.5 V

7 V

3 V

0 V

3 V

0 V

Input

(see Note B)

PLH

Output

PHL

Output

PROPAGATION DELAY TIMES

INVERTING AND NON-INVERTING OUTPUTS

NOTES: A. CL includes probe and jig capacitance.

B. All input pulses are supplied by generators having the following characteristics: PRR ≤ 10 MHz, ZO = 50 Ω, tr ≤ 2.5 ns, tf≤ 2.5 ns.

C. Waveform 1 is for an output with internal conditions such that the output is low except when disabled by the output control.

Waveform 2 is for an output with internal conditions such that the output is high except when disabled by the output control.

D. The outputs are measured one at a time with one transition per measurement.

1.5 V 1.5 V

1.5 V

VOLTAGE WAVEFORMS

Figure 13. Load Circuit and Voltage Waveforms

PHL

1.5 V

PLH

1.5 V1.5 V

3 V

0 V

Output

Control

Output

Waveform 1

S1 at 7 V

(see Note C)

Output

Waveform 2

S1 at Open

(see Note C)

1.5 V

PZL

PLZ

1.5 V

PZH

ENABLE AND DISABLE TIMES

LOW- AND HIGH-LEVEL ENABLING

PHZ

1.5 V

VOLTAGE WAVEFORMS

1.5 V

VOL + 0.3 V

VOH – 0.3 V

3 V

0 V

3.5 V

[

0 V

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page 30

IMPORTANT NOTICE

T exas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability.

TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary to support this warranty . Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements.

CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICA TIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERST OOD TO BE FULLY AT THE CUSTOMER’S RISK.

In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards.

TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of TI covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used. TI’s publication of information regarding any third party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.

Datasheet SN74ABT18502PM Datasheet (Texas Instruments)

Specifications and Main Features

Frequently Asked Questions

User Manual