RED_80 computer

Currently work in progress.

Repository content

BOM

• CMOS z80 CPU
• AS6c62256 32k*8bits CMOS low power SRAM
• CMOS 4011 quad NAND logic gate
• CMOS 4071 quad OR logic gate
• CMOS 40106 hex trigger
• 1x tactile switch
• 3x poalized electrolytic 0.01uF capacitor
• 2x ceramic (unpolarized) 22pF capactitor
• Crystal (freq. TBD)
• 1x 10k resistror
• 1x 1M resistor

Memory map

memory address	Usage
0x0000 - 0x1FFF	ROM
0x2000 - 0x3FFF	EXT ROM
0x8000 - 0xFFFF	RAM

ROM content

• 0x0000 system reset/init
• memroy monitor

Serial interface

System has been designed to be interfaced with a French Minitel 1B made by MATRA communication terminal.

Serial output is slow (by design). Serial interface configuration :

• 4800 baud
• 7bit DATA
• 1bit STOP
• Even parity
• No flow control

To be able to use, you need to setup the minitel in the right comunication mode. Do in order

1. Fonction+T, A Activate "Péri-Informatique" mode
2. Fonction+T, E Deactivate local character echo
3. Fonction+P, 4 Set baudrate to 4800

Minitel interface can be adapted to serial using the assoRED/MinitelInterface circuit