Aeroflex Circuit Technology

SCDCT1990 REV B 8/21/00 Plainview NY (516) 694-6700

13

RT/BC

INPUT

Remote Terminal/Bus Control - This line when high causes the ASIC to

function as a remote terminal. When low the ASIC functions as a bus controller

or passive monitor.

DBCACC

INPUT

Dynamic Bus Control Accept - This line should be permanently tied low if a

subsystem is able to accept control of the bus if offered.

LTFAIL

OUTPUT

Loop Test Fail - This line goes low if any error in the transmitted waveform is

detected or if any parity error in the hardwired RT address is detected.

ERROR

OUTPUT

Error - This line latches low if a Manchester or parity error is detected. It is

reset by the next CMSYNC (RT mode) and also by RTO in the BC mode.

RTO

OUTPUT

Reply Time Out - This signal will pulse low whenever the reply time for a

transmitting terminal has been exceeded. This line is intended for the bus

controller use.

TXTO

OUTPUT

Transmitter Time Out - This line goes true if the transmitter time out limits are

exceeded.

PARER

OUTPUT

Parity Error - This line will pulse low if a parity error is detected by the

decoder.

MANER

OUTPUT

Manchester Error - This line will pulse low if a Manchester error is detected by

the decoder.

DBCREQ

OUTPUT

Dynamic Bus Control Request - This line will pulse low when the status reply

for a mode code Dynamic Bus Control has finished where the accept bit was

set.

VALD

OUTPUT

Valid Data - This line will pulse low when a valid data word is received.

DRVINH

INPUT

Driver Inhibit - Selects on-line or off-line testing during automated self test.

When high self test is on-line. Must be high when LTEN is high. CT1991 only.

LTEN

INPUT

Loop Test Enable - Enables automated self-test when low. Normally high.

CT1991 only.

LTTRIG

INPUT

Loop Test Trigger - When pulsed low while LTEN is low automated self-test is

initiated. LTEN pulse width should be 100ns < PW < 5µs. CT1991 only.

Pin Description (Cont.)

Signal

Direction

Signal Description