The TPS25961's exposed pad is GND and the datasheet requires it be connected
to the GND plane (Table 5-1; package note 3 adds a mechanical requirement).
REVIEW.md claimed this was honoured because the footprint is the _ThermalVias
variant -- but the variant alone connects nothing. hardware/TPS25961.kicad_sym
defined pins 1-6 only, with no pin for the exposed pad, so KiCad had nothing to
map onto footprint pad 7 and left it netless: an isolated copper island under
the chip with its thermal vias going nowhere.
Adds pin 7 (GND, power_in, hidden, stacked on pin 4) to the symbol library, the
cached symbol in exi.kicad_sch, and the U13 instance.
PCB updated and verified: U13 pad 7 carries GND on all four elements (both SMD
rects and both thermal vias), R48 placed, EFUSE_OVLO routed, R49 gone. DRC
reports 0 violations, 0 unconnected pads and 0 schematic parity issues -- the
0-unconnected result is what confirms pad 7 is tied into the GND network rather
than merely labelled. The 4 DRC errors previously dismissed as zone-fill
phantoms on this pad are gone, though zones were refilled in the same pass so
that is not proof of cause either way.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Devcontainer now grants libusb access to the FT2232H so iceprog (bitstream) and
pyftdi (FT2232H EEPROM) run inside the container:
- devcontainer.json: --privileged + /dev/bus/usb bind mount
- Dockerfile: sudo (NOPASSWD for vscode; USB nodes are root-owned), libusb-1.0-0,
libftdi1-2, pyftdi
Add the flash-re-bba-rb skill documenting the procedure (bitstream via best swept
seed, optional EEPROM string, troubleshooting, guardrails) and
flash_ftdi_eeprom.py (pyftdi, backup-first, dry-run default) + ftdi_eeprom.conf
value spec.
Bring-up on the repaired V1 unit: bitstream flash VERIFY OK (iceprog
build/seed4/top.bin, capture 58.36 MHz). EEPROM product string CANNOT be
programmed on V1 — U7 is a 93LC46B (128 B), too small for the FT2232H, which
needs a 93LC56B (256 B); the 128 B chip mirrors and the config write fails
verify. This overturns the old REVIEW note "93LC46B = correct for FT2232H"
(that only checked ORG, not size). Board still works blank -> ROM defaults;
iceprog + UART unaffected. Documented in REVIEW.md + TODO.md (swap U7->93LC56B
for V2); flash_ftdi_eeprom.py detects the mirroring and refuses the write.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Store datasheets for the parts actually placed in the current design,
grouped under hardware/re-bba-rb/datasheets/ by sheet (fpga, power,
usb, ethernet). Filenames normalised to the part MPN. All tracked
through git-lfs per .gitattributes (*.pdf).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Roflin
Dennis Brentjes