Datasheet

SN54ABT8543, SN74ABT8543
SCAN TEST DEVICES WITH
OCTAL REGISTERED BUS TRANSCEIVERS
SCBS120E – AUGUST 1991 – REVISED JULY 1996
4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Terminal Functions
TERMINAL
NAME
DESCRIPTION
A1–A8 Normal-function A-bus I/O ports. See function table for normal-mode logic.
B1–B8 Normal-function B-bus I/O ports. See function table for normal-mode logic.
CEAB, CEBA
Normal-function chip-enable inputs. See function table for normal-mode logic.
GND Ground
LEAB, LEBA
Normal-function latch-enable inputs. See function table for normal-mode logic.
OEAB, OEBA
Normal-function output-enable inputs. See function table for normal-mode logic.
TCK
Test clock. One of four terminals required by IEEE Standard 1149.1-1990. Test operations of the device are synchronous to
TCK. 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 terminals required by IEEE Standard 1149.1-1990. TDI 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.
TDO
Test data output. One of four terminals required by IEEE Standard 1149.1-1990. TDO is the serial output for shifting data
through the instruction register or selected data register.
TMS
Test mode select. One of four terminals required by IEEE Standard 1149.1-1990. TMS directs the device through its TAP
controller states. An internal pullup forces TMS to a high level if left unconnected.
V
CC
Supply voltage