SDD 7612fcbda9 reference: LANCE loopback-FCS datasheet evidence (MAME condition is right) ...

Add the Am7990 Technical Manual and Am79C90 datasheet to
reference/lance-datasheet/ and a report, reference/lance-loopback-fcs.md,
that answers whether MAME's am79c90 receive() FCS condition
(!(MODE_LOOP) || MODE_DTCR) is inverted.

Verdict: MAME is right. The CRC generator and checker share one circuit,
so with LOOP=1 the receiver can only check the FCS when DTCR=1 -- exactly
what MAME does. The proposed inversion would be wrong in both loopback
cases. No MAME change made.

2026-10-16 16:46:47 +03:00

..

duart-datasheet

reference: DUART datasheet verification of the two mc68681 edits (claim 1 refuted)

2026-10-16 12:13:07 +03:00

fonts

checkpoint: VT1200 reverse-engineering workspace before board-model work

2026-10-16 01:37:50 +03:00

keyboard-mouse

docs: PROTOCOL.md tablet coordinate range (0..2199) and the device-code discriminator, confirmed against the running OS

2026-10-16 16:10:11 +03:00

l1probe

reference: level-1 host-port test — can it be skipped? (analysis, no skip)

2026-10-16 12:42:35 +03:00

lance-datasheet

reference: LANCE loopback-FCS datasheet evidence (MAME condition is right)

2026-10-16 16:46:47 +03:00

vt1200-boot-video

reference: commit the real-boot frame evidence (33MB) with a NOTES.md; gitignore the 201MB source recording

2026-10-16 16:22:59 +03:00

vt1200-photos

checkpoint: VT1200 reverse-engineering workspace before board-model work

2026-10-16 01:37:50 +03:00

x11

checkpoint: VT1200 reverse-engineering workspace before board-model work

2026-10-16 01:37:50 +03:00

x11-fontsrc

checkpoint: VT1200 reverse-engineering workspace before board-model work

2026-10-16 01:37:50 +03:00

dis34-a-v21.txt.gz

checkpoint: VT1200 reverse-engineering workspace before board-model work

2026-10-16 01:37:50 +03:00

dis34-a-v22.txt.gz

checkpoint: VT1200 reverse-engineering workspace before board-model work

2026-10-16 01:37:50 +03:00

dis-bank0.txt

checkpoint: VT1200 reverse-engineering workspace before board-model work

2026-10-16 01:37:50 +03:00

lance-loopback-fcs.md

reference: LANCE loopback-FCS datasheet evidence (MAME condition is right)

2026-10-16 16:46:47 +03:00

level0-10byte-puzzle.md

reference: the level-0 10-byte puzzle -- count-only, no loopback, no 10-byte device message

2026-10-16 14:16:37 +03:00

level1-bypass-analysis.md

docs: correct Q4 of the level-1 bypass analysis -- a level-1 failure is NOT fatal (superseded answer kept as record)

2026-10-16 14:57:54 +03:00

level1-test-sequence.md

docs: level-1 test sequence, port tests vs device tests (keyboard/mouse device models needed for tests 26/27)

2026-10-16 11:31:56 +03:00

mc68681-counter-period.md

reference: DUART counter/timer period when CTUR/CTLR unprogrammed -- datasheet does not settle it

2026-10-16 15:00:20 +03:00

mc68681-datasheet-verification.md

reference: DUART datasheet verification of the two mc68681 edits (claim 1 refuted)

2026-10-16 12:13:07 +03:00

memory-space-map.md

docs: memory-space map from the spike; commit the plan amendment; ignore harness logs

2026-10-16 02:15:13 +03:00

plan-1-board-model-outcome.md

docs: plan-1 outcome, rulings, and triaged findings (durable record before workspace cleanup)

2026-10-16 02:15:51 +03:00

rom-strings.txt

checkpoint: VT1200 reverse-engineering workspace before board-model work

2026-10-16 01:37:50 +03:00

VT1000-v1.2-ROM-dump.files.txt

checkpoint: VT1200 reverse-engineering workspace before board-model work

2026-10-16 01:37:50 +03:00

VT1000-v1.2-ROM-dump.zip

checkpoint: VT1200 reverse-engineering workspace before board-model work

2026-10-16 01:37:50 +03:00