Datasheet

SN74ABT18502
SCAN TEST DEVICE
WITH 18-BIT REGISTERED BUS TRANSCEIVER
SCBS753 – FEBRUARY 2002
4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Terminal Functions
PIN NAME DESCRIPTION
GND Ground
TCK
Test clock. One of four pins required by IEEE Std 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.
TDI
Test data input. One of four pins required by IEEE Std 1149.1-1990. TDI is the serial input for shifting data through the
instruction register (IR) or selected data register (DR). An internal pullup forces TDI to a high level if left unconnected.
TDO
Test data output. One of four pins required by IEEE Std 1149.1-1990. TDO is the serial output for shifting data through
the IR or selected DR.
TMS
Test mode select. One of four pins required by IEEE Std 1149.1-1990. The TMS input directs the device through its TAP
controller states. An internal pullup forces TMS to a high level if left unconnected.
V
CC
Supply voltage
1A1–1A9,
2A1–2A9
Normal-function A-bus I/O ports (see function table for normal-mode logic)
1B1–1B9,
2B1–2B9
Normal-function B-bus I/O ports (see function table for normal-mode logic)
1CLKAB, 1CLKBA,
2CLKAB, 2CLKBA
Normal-function clock inputs (see function table for normal-mode logic)
1LEAB, 1LEBA,
2LEAB, 2LEBA
Normal-function latch enables (see function table for normal-mode logic)
1OEAB, 1OEBA,
2OEAB
, 2OEBA
Normal-function output enables (see function table for normal-mode logic)