Motorola CPCI-6020 manual 134

Transition Module Preparation and Installation Serial Interface Module Circuitry

The EIA-232-D SIMs employ MC145406 ICs as line transmitters to convert the TTL output signals from the CPCI-6020 module 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 CPCI-6020. For all port interfaces, the SIMs support the transmitter signal element timing as either input or output signals.

The MC145406 transceiver IC requires a series diode on the +12 V supply and a clamp diode to logic ground on the -12 V supply. The diodes are located on the transition module rather than on the SIM due to space limitation.

134 CPCI-6020 CompactPCI Single Board Computer Installation and Use (6806800A51C)