Quazar OLED interface

Official site: https://2014.samcoupe.com/#graphicoled

Based on SSD1305 OLED display (128x32 version?): SSD1305.pdf

Uses 0x50 I/O port by default (fully configurable). I/O decoder uses 74HCT02 NOR gates and 74GCT688 8-bit comparator.

The SSD1305 chip is placed behind two 74HCT573 8-bit latches so it can be timed slower than Z80 bus:

• One latch takes 8 bit data bus and forwards to the OLED chip.
• The other latch takes 3 control bits from higher address buss byte as output from B register.
• Latches take input on I/O bus write when base address matches.
  • Compactor is enabled when RW and IORQ are active (low).
  • If address matches the I/O address select the latches will copy and store data from data bus and first 3-bits from high address byte.
  • The latched data is presented to OLED until the next I/O write to the card occurs.

Software

I have implemented a program to display images using instructions form provided manual:

•  rc2014-oled - oled program for CP/M and PNG image converter.