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.
Pin | Function | Pin | Function |
---|---|---|---|
1 | a | ||
2 | b | ||
3 | c | ||
4 | d | ||
5 | e | ||
6 | f | ||
7 | g | ||
8 | h |
CON2 (Expansion)
CON3 (RS232)
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
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