ZMJC Computer

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Introduction

During my MSc in Electrical and Electronic Engineering at The University of Nottingham (1992-3) we used this single boad computer for an assembly programming module. It must have been designed by one of the university staff, but I don't know who; it is just labelled "© 1991 MJC". Hence, I will refer to this as the zMJC Computer. I lost the schematic many years ago.

Key features:

  • Z80180 CPU (z80 compatible) running at 6 MHz
  • 256 KB EPROM
  • 8 KB RAM (32 KB or 128 KB options)
  • 8 bit switch input
  • 8 bit LED output
  • RS232 option
  • ZN559 DAC option
  • AD7828 OR ACD0809 ADC option


It is intended that this page will ultimately document the schematic and repoducible PCB layout after I have reverse engineered it.

Connectors

CON1 provides connection to the ADC and DAC options.

Pin Function Pin Function
CON1: ADC/DAC
1a 1b
2a 2b
3a 3b
4a 4b
5a 5b
6a 6b
7a 7b
8a 8b

CON2 (Expansion)

CON3 (RS232)

Pin Function Pin Function
CON4: Power
1a +5 V DC 1a +5 V DC
2a 0 V 2b 0 V
3a 3b
4a 4b
5a 5b
6a 6b
7a 7b
8a 8b

Jumpers:

  • RESET: Closes to reset
  • RAMSIZE: 8 HB or 32 KB/128 KB

Memory Map

Start End Function
Main Memory
8000H RAM
0000H 7FFFH ROM
Port Function
IO Ports
90H Switch Input
88H DAC Output
87H ADC Input 8
86H ADC Input 7
85H ADC Input 6
84H ADC Input 5
83H ADC Input 4
82H ADC Input 3
81H ADC Input 2
80H ADC Input 1

Circuit Description

TBC

Software

TBC