Skip to content

Morley A3000 User and Analogue Port

Jump to bottom
sarah-walker-pcem edited this page Sep 27, 2021 · 1 revision

Register description

IOC address map :
  0000-1fff - ROM
  2000-2fff - 6522 VIA
    PA0-PA2 - ROM bank
    PA6 - Analogue fire button 0
    PA7 - Analogue fire button 1
    PB0-7, CB1, CB2 - User port

MEMC address map :
  1000-1fff - ADC

Notes

Expansion card header is at ROM address 0x3800 (ROM bank 7). VIA port A is set to all input on reset, which results in the ROM high bits being pulled high. The loader will switch PA0-PA2 between input to read the header and chunk directory, and output to read module data.

Early cards also have an external I2C port. This was removed at some point.

Links

Chris's Acorns: Morley Electronics User I2C Analogue mini-podule

Clone this wiki locally