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
98H LED Output
8000H RAM
0000H 7FFFH ROM
Port Function
98H LED Output
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