MIL-DTL-62737A

Abstract

This specification covers a Computer Printed Wiring Assembly, referred to herein as the PWA. This is one of six printed wiring assemblies that comprise the Simplified Test Equipment/Internal Combustion Engine-Reprogrammable (STE/ICE-R) Vehicle Test Meter (VTM) (see Drawing 12259265). <b><u>Intended Use:</u></b> The printed wiring assemblies of the STE/ICE-R vehicle test set determine primary fault isolation of a vehicle engine, fuel or electrical system. The PWA contains an 8-bit microprocessor with 16-bit memory addressing and has an interrupt input and four-event flag inputs. There are two banks of memory; a 23k by 8 ultraviolet Erasable Programmable PROMs which are removed for updated and reprogrammable memory via another VTM (EEPROM's; U2-U7). An 8k by 8 Static Random Access Memory (SRAM; U8) is accessible from both banks. The microprocessor runs on either a 4 MHz or 2 MHz clock, which is software selectable. Logic levels on the external input lines can be gated onto the data BUS (pins 21 through 28; board and IC pins will be designated P1-XX and UZ-XX, where XX is the pin number and Z is the IC number). A bus transceiver isolates the microprocessor and memory from the rest of the data BUS. The PWA is military unique because it is designed specifically to be a component of the Simplified Test Equipment/Internal Combustion Engine - Reprogrammable (STE/ICE-R) Vehicle Test Meter (VTM), and to withstand environmental conditions which exceed commercial requirements. <br>