ZMJC Computer

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.

CON1: ADC/DAC

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

CON3 (RS232)

CON4: Power

Pin	Function	Pin	Function
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

Main Memory

Start	End	Function
98H	LED Output
8000H		RAM
0000H	7FFFH	ROM

IO Ports

Port	Function
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