CydandClaude Opus 4.8 2dca8bfd8f PlasmaNew: firmware dump + reverse-engineering analysis ...

Adds the dumped U3 EPROM image (tms27pc512.BIN) and the analysis it enabled.

Findings (FIRMWARE.md):
- Memory map: code+data at CPU $8000-$FFFF (EPROM upper 32KB, 1:1); lower
  half unused. Valid HC11 vectors; SCI rx ISR at $B85C fills a ring buffer,
  main-loop parser dispatches.
- Full command set recovered from the two jump tables: 58 ESC commands
  ($98AC) + control chars ($994C). Decoded semantics for @/G/H/K/L (confirm
  earlier guesses) plus NEW commands: Q=set-row, R=set-col, I=draw-page,
  i=display-page (10-page double-buffering), A-F=vector graphics, X/Y=pen.
- 8 fonts at $BC03 (6x8, 6x10, 7x10, 12x16, 12x20); glyph bitmaps in ROM
  (~$C000-$DFFF, exact base TBD).
- Built-in demo enabled by jumper 6 (confirms the JP1 map).

Tooling: hc11dis.py, a purpose-built 68HC11 disassembler (the toolchain has
no m68hc11 target), with the analysis reproducible from the addresses noted.

The firmware is now the authoritative command spec, superseding the need for
the Babcock programming manual. Feeds both vPLASMA and the replica firmware.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

2026-07-16 17:13:11 -05:00

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