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Me Here 2f44be6f63 PM_K-1 hardware: resolve TQ2SA relay pinout; Stage 2 DAC + reconstruction filter 
Relay residuals resolved from the Panasonic TQ-SMD connection diagram + contact-
resistance terminal pairs: coil=1/10, pole1 COM=3/NC=4/NO=2, pole2 COM=8/NC=7/NO=9,
pins 5/6 unused. (NC/NO sense also firmware-correctable via the GPIO drive.)
Stage 1b encoding already matched; docstring updated to "resolved".

Stage 2 (click source): PCM5102A DAC + 2nd-order Sallen-Key reconstruction filter.
- PCM5102A pinout verified (TI SLAS859C, TSSOP-20). 2.1Vrms GND-centered out (no
  DC-block), charge-pump flying cap + VNEG, DEMP/FLT/FMT tied for I2S/normal/no-deemph,
  SCK<-low-jitter MCLK, BCK/DIN/LRCK<-RP2350, XSMT pulled-up soft-mute.
- OPA1612 Sallen-Key LPF on OUTL. stage2_recon.cir confirms flat to 20kHz, -3dB at
  74.8 kHz -- cleans delta-sigma HF residue without touching audio.
- ERC 0 errors; netlist 0 errors.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-05-30 20:06:26 -05:00
..
circuits PM_K-1 hardware: resolve TQ2SA relay pinout; Stage 2 DAC + reconstruction filter 2026-05-30 20:06:26 -05:00
sim PM_K-1 hardware: resolve TQ2SA relay pinout; Stage 2 DAC + reconstruction filter 2026-05-30 20:06:26 -05:00
Containerfile PM_K-1 hardware: Stage 1 input receiver as SKiDL (code-defined schematic) 2026-05-30 19:43:07 -05:00
README.md PM_K-1 hardware: reproducible EDA container (KiCad 9 + ngspice) 2026-05-30 19:17:54 -05:00
run.sh PM_K-1 hardware: reproducible EDA container (KiCad 9 + ngspice) 2026-05-30 19:17:54 -05:00

README.md

PM_K-1 EDA environment

A reproducible container with the tools to design, check, and simulate the core board — so the work doesn't depend on whatever happens to be installed on a given machine, now or in 50 years.

What's inside

  • KiCad 9 — schematic capture + PCB layout, and a CLI (kicad-cli) that can run ERC (Electrical Rules Check) and DRC, and export netlists/PDF/Gerbers.
  • ngspice — SPICE simulator for validating the analog audio circuits before we commit copper (op-amp stages, filters, input loading, etc.).
  • python3 — scripting, BOM munging, optional code-defined-schematic helpers.

Why a container?

The system KiCad here is 7.0, whose CLI can't run ERC (that arrived in KiCad 8). Rather than fight the host, we pin a known toolchain. Anyone — including future-you — rebuilds the exact environment with one command.

Use it

cd hardware/eda
./run.sh                                   # interactive shell, lands in hardware/kicad/
./run.sh kicad-cli version                 # confirm KiCad 9
./run.sh kicad-cli sch erc pm_k1_core.kicad_sch   # run ERC on the schematic
./run.sh ngspice -b ../eda/sim/input_loading.cir  # run a simulation (cwd is kicad/)

run.sh builds the image on first use, then mounts the whole repo at /work (so KiCad sees hardware/). Use RUNTIME=docker ./run.sh … to use Docker instead of Podman.

Layout

eda/
  Containerfile      # the pinned toolchain (KiCad 9 + ngspice + python)
  run.sh             # build-if-needed + run with the repo mounted
  sim/               # ngspice decks (SPICE simulations of the analog circuits)