Technical data

Serial Interface Module Circuitry Functional Description
MVME7616E Transition Module Installation and Use (6806800A43B)
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The timing relationships among MXCLK, MXSYNC#, MXDO, and MXDI are illustrated in the
next figure.
3.4 Serial Interface Module Circuitry
Each Serial Interface Module has a 60-pin connector that provides all signal and power
connections to the MVME761 transition module.
TTL-level signals
All TTL-level signals, with the exception of data and clocks, are active low. The pullup resistors
on the MVME761 transition module drive all TTL inputs to the SIM to a known logic level.
SIMs
The SIMs have surge suppression circuitry for all port signals going to the external connector.
This consists of a series resistor and a dual 15V clamp diode to chassis ground. All series
resistors are 100 ohms except on the EIA-530 balanced drives, which use 10 ohm series
resistors.
EIA-232-D SIMs employ MC145406 ICs as line transmitters to convert the TTL output signals
from the host VMEmodule to EIA-232-D voltage levels. As line receivers, the MC145406 ICs
convert the EIA-232-D input signals to TTL voltage levels which are sent to the VME module.
The MC145406 transceiver IC requires a series diode on the +12V supply and a clamp diode
to logic ground on the -12V supply. The diodes are located on the transition module rather than
on the SIM due to space limitations.
For all port interfaces, the SIMs support the transmitter signal element timing as either input or
output signals.
Figure 3-4 Multiplex Signal Timing Chart
RTS3 DTR3 LLB3 RLB3Reserved
CTS3 DSR3 DCD3 TM3DCD2
MXCLK
MXSYNC#
MXDO
MXDI
Time Slot 15 Time Slot 0
Time Slot 1 Time Slot 2
Time Slot 3
11640.00 9611