ZMJC Computer

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Introduction

During my MSc in 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, 32 or 128 KB RAM
  • RS232
  • ZN559 DAC option
  • AD7828 OR ACD0809 ADC option
  • 8 bit switch input
  • 8 bit LED output

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
1 a
2 b
3 c
4 d
5 e
6 f
7 g
8 h

CON2 (Expansion)

CON3 (RS232)

Pin Function Pin Function
CON4: Power
1 +5 V DC a +5 V DC
2 0 V b 0 V
3 c
4 d
5 e
6 f
7 g
8 h

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
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