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>
The cockpit PCs are now Win x64, so the replica needs no real RS-232 — a
native-USB MCU presenting as a USB CDC virtual COM port is transparent to
the host (opens COMx, can't tell it isn't a UART). Records the consequences
(baud cosmetic, timing instant, pin the COM number, LEDs need their own
power) and marks the hardware/protocol thread parked until the U3 EPROM
firmware dump (or Babcock programming manual) is in hand.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Historical reference for recreating the cockpit plasma display in hardware.
The original Babcock plasma panels are failing; the end goal is a drop-in
replica — a modern microcontroller driving a 128x32 LED array that reads the
same RS-232 serial bus and speaks the same command protocol as the original
PD01D221. vPLASMA (the C# app) is the executable spec and test oracle for
that firmware.
Contents:
- PD01D221.pdf — Babcock datasheet (doc 9200-0109 Rev A)
- Board photos: controller overview, Cherry silkscreen, EPROM/SRAM, JP1
- README.md — full investigation: hardware ID (stock Babcock PD01D221,
Cherry PCB 4317-C), chip inventory, recovered ESC command protocol, the
JP1 config-jumper map (MODA/MODB hardwired to expanded mode), and the
firmware-dump plan.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
CydandClaude Opus 4.8