SN54LVT18502

3.3-V ABT SCAN TEST DEVICE

WITH 18-BIT UNIVERSAL BUS TRANSCEIVERS

SCBS669 – JULY 1996

4

POST OFFICE BOX 655303

Terminal Functions

TERMINAL NAME

DESCRIPTION

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.

GND

Ground

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. An internal pullup at each terminal forces the

terminal to a high level if left unconnected.

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.

VCC

Supply voltage