New IO-ARCHITECTURE.md, derived from the v4.2 image, the U7 GAL decode
and schematic sheets 1/3:
- $A010 control-latch bit map (CCK / D_OUT / WR_SB / RD_SB / SEL0-2)
- the 50-byte script format the firmware replays, and the ROM table map
- full port/address population: 9 buttons boards + 2 keypads across all
8 ports; the 0x00-0x6F logical map and its 0x48-0x4F gap
- the keypad engine ($CC53/$CC7E): 4-row matrix scan, row-patched RAM
scripts, the $DC14 key-code table, message type $8B
- lamp readback ($21C2) and the 72-byte lamp-fault mask at $DFA8 --
fault reports are type $03 with the lamp index in $2519
- scan cycle budget: 1.91 ms/pass, 17.3 ms/scan, ~58 Hz; demux is 60%
- expansion: one spare buttons board, and nothing further without a
protocol revision
Corrections to existing docs:
- $CC53 was cited as the encoder sweep; it is the keypad-1 scanner.
The sweep is $C8CC-$C9A7, driven from $C0CB.
- U31 is on sheet 3, not sheet 1, and is completely uncommitted: no
address, data, strobe or pod-bus signal reaches it. Not an expansion
hook -- populating it does nothing without new wiring.
- No spare HCTL-2016 footprints exist. The decode has 3 free selects on
U9, but the PCB carries exactly 5 positions and sheet 1 draws 5.
More analog axes need hardware, not firmware.
Also carries the previously-uncommitted standard-rate (16550)
feasibility analysis and baudscan.py, plus a note that the FastRIO
"FTDI-class adapter" rule really means arbitrary-rate generation:
CP2102N qualifies, classic CP2102 snaps 31250 to 38400. Bench-measured
2026-07-26; on-cockpit latency check still pending.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Sibling links (hardware<->firmware) now resolve within restoration/;
links to RIOjoy's PROTOCOL.md and Win32RIO/ (which stayed in the RIOjoy
repo) point to gitea web URLs.
Board photos, scanned schematics, and GAL fuse-map decode of the
physical RIO board set.
git-subtree-dir: restoration/rio-hardware
git-subtree-mainline: def5840e07
git-subtree-split: 42b3944ebe
CydandClaude Opus 5