julien/typewriter
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

docs(adr): record ADR-012 — SD on its own SPI3 host

Browse Source 
Document the shared-bus arbitration decision: rather than rework the
proven EPD SPI layer and add a cross-thread mutex on the save path, the
SD moves to a dedicated SPI3. Update the boot sequence, risk table,
Spike 3 postmortem follow-up, hardware overview, and firmware README.
This commit is contained in:
Julien Calixte
2026-07-11 11:28:22 +02:00
parent 9129f04d0e
commit 4bc9236bd7
5 changed files with 80 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
docs/hardware.md
View File

@@ -29,6 +29,6 @@ The board is on the bench and bring-up is largely done — per-spike results
live in [`spikes.md`](spikes.md) and
[`v0.1-mvp-technical.md`](v0.1-mvp-technical.md#hardware-bring-up-order),
with failure write-ups in [`postmortems/`](postmortems/README.md). Notable: the
keyboard runs bus-powered on the S3's native USB port, and SD wiring is
proven on shared SPI2 but blocked on a compatible ≤32 GB card
([postmortem](postmortems/2026-07-05-spike3-sd-cmd59.md)).
keyboard runs bus-powered on the S3's native USB port, and the SD/FAT stack is
verified on a 32 GB card (2026-07-11), now moving to its own SPI3 host per
ADR-012 ([postmortem](postmortems/2026-07-05-spike3-sd-cmd59.md)).