tag

#atari-st

2 posts

RetrogamingDeep Dive October 4, 2026 8 min read

Atari ST MC68901 MFP: Timer Modes, Interrupt Priority, and In-Service State

Trace Atari ST MFP timers and interrupts from prescaler events through pending, mask, priority, and in-service registers, with repeatable diagnostic fixtures.

#atari-st#mc68901#mfp

RetrogamingDeep Dive October 4, 2026 8 min read

Atari ST Shifter Screen Fetching: Base Registers, Address Counter, and MMU Timing

Track Atari ST screen-base alignment, Shifter fetch addresses, resolution-dependent memory use, and MMU arbitration across ST and STE hardware.

#atari-st#shifter#mmu