BRINGUP.md is the cold-start reference: project status (audit phases 0-5 complete, Phase 6 spike achieved - first grblHAL-commanded motion 2026-07-26), bench/board access, build+deploy procedures, the step backend runbook incl. the required analog machine config, the measured hardware facts bank, and the ordered next-work list. scripts/bench/ preserves the hardware-verification tools (underrun feeder, end-of- data protocol bench, PWM register check, cross-build scripts).
6.8 KiB
ForgeFIRM bring-up status & cold-start runbook
Last updated: 2026-07-26 — the day the machine first moved under grblHAL.
Read together with AUDIT_ACTION_PLAN.md in the project root (sibling of
this repo; per-finding status of the 2026-07-03 audit) and
kernel-module-glowforge/UAPI.md (the pulse-stream feeder contract).
Where the project stands
Audit phases 0–5: complete and hardware-verified. Both motion blockers
fixed (cnc probe / 40v-supply; SDMA script relocated to <26 0xF00> with a
pre-run integrity guard); the end-of-data protocol reworked and bench-proven
(underrun is a first-class underrun state behind the streaming attr;
16/16 protocol bench); laser PWM verified at 39.98 kHz (register level);
CONFIG_PREEMPT=y; uEnv/u-boot/ulfius build integrity restored; legacy
cloud mode repaired (nvmem identity → hostname XXX-XXX verified on fuses;
deadman/safety loop; camera error paths).
Phase 6 spike: achieved.
- grblHAL (unmodified core) runs on the board, speaking Grbl 1.1f over TCP port 23 (LightBurn-confirmed).
- Underrun proof: 100 kHz × 120 s under full load, 150 ms queue, 0.2 ms worst write latency, zero underruns. Measured SDMA script ceiling: ~165 kHz effective (~6 µs/byte).
- The step backend works: the driver resamples grblHAL's step
events into pulse bytes and live-feeds
/dev/glowforge. X and Y jogs from TCP G-code move the real gantry; grblHAL and kernel position counters agree step-for-step. Motion-only: the laser latch is forced locked, byte bit 4 is never emitted.
The bench
- Board: SSH
root@172.16.1.130, empty password (ssh -o PreferredAuthentications=nonelogs straight in). Dev image (forgefirm-image-dev) on SD; BusyBox userland + python3 + gdb/strace. Serial console on ttymxc0 available at the bench. - Deploying kernels: re-burn the SD with the freshly built
forgefirm-image-dev-glowforge.rootfs.wic.gz(deploy dir below). Where the boot flow loads the kernel from was never fully traced (the wic has no boot partition; the eMMC env area reads empty) — re-burning works and is the procedure. Module-only changes hot-swap: scpglowforge.koover/lib/modules/<kver>/extras/, thenrmmod glowforge && modprobe glowforge. NOTE: a module reload turns off the lid LED (relight via/sys/class/leds/lid_led*/target) and resets analog config (below). - Build host: WSL2 distro
forge-yocto, tree at~/dev/openglow-forgefirm.~/src-sync.shrsyncs the Windows repos in (now includespython3-gfhardware). Build:cd ~/dev/openglow-forgefirm/forgefirm && kas shell kas/forgefirm-glowforge.yml -c 'bitbake forgefirm-image forgefirm-image-dev'. Artifacts:forgefirm/build/tmp/deploy/images/glowforge/. - Shell gotchas (cost real time): PowerShell mangles embedded double
quotes in git-commit here-strings (avoid
"in messages);wsl -- bash -c '...'eats$VARexpansions (use script files run via PowerShell, not Git Bash, which MSYS-mangles/mnt/cpaths).
Running the step backend (grblHAL on the board)
Source: the ForgeFIRM grblHAL step backend (grblHAL core + the glowforge pulse-stream sink).
- Build: cross-compile the backend in the forge-yocto WSL distro (from
PowerShell). Produces
build-arm/grblHAL_glowforgein the WSL tree (-O1 -g,GLOWFORGE_DEFAULTS=ON→ machine scaling baked in: 53.333 µsteps/mm XY @ ×8, 2.832 half-steps/mm Z, 0.417" Z travel). - Deploy to
/usr/bin/grblHAL_glowforgeon the board. - Analog machine config — required after every module reload/boot; the
kernel does NOT do this (the cloud stack normally did):
echo 150 > /sys/glowforge/pic/x_step_current # run current; 33 = weak hold. echo 150 > /sys/glowforge/pic/y_step_current # Factory-true values TBD echo 8 > /sys/glowforge/cnc/x_mode # ×8 microstepping to match echo 8 > /sys/glowforge/cnc/y_mode # the baked steps/mm echo 8 > /sys/glowforge/cnc/motor_lock # Z locked; X/Y free echo 1 > /sys/glowforge/cnc/laser_latch # laser locked out - Start:
cd /data && GFSINK=/dev/glowforge grblHAL_glowforge -p 23 -n -t 1.0(-t 1.0is REQUIRED: the real-time throttle is what bounds the queue). Env knobs:GFSINK_RATE(machine tick, default 10000 Hz),GFSINK_DEPTH_MS(queue depth = feed-hold latency, default 200). - Connect LightBurn/UGS to
172.16.1.130:23, or jog raw:$J=G91X40F1200.
Hardware facts bank (measured)
- SDMA pulse engine: ring free = 128 MiB − 32 KiB gap; script effective
ceiling ~165 kHz; position counters (
sdma_contextsc0/1/2 = X/Y/Z steps, sc3 = bytes) match grblHAL exactly. - Byte layout & rules: see the UAPI.md feeder contract (authoritative).
- Z: bit 6 SET = lens UP = +Z (hardware-verified; pulsedata.py was the inverted party, fixed). Home = hall trigger at TOP; usable travel ≈ 30 half-steps ≈ 10.6 mm ≈ 0.417"; 0.3534 mm/half-step. Never blind-drive Z — hall-supervised only.
- XY: 0.15 mm per full step; DIR bit set = −X / +Y (Y1/Y2 complementary).
- Laser PWM: 39.98 kHz register-verified (divider 13 × 127 counts).
- Switches: truthy = closed/OK; SW_INTERLOCK reads False on units without the rear plug — must NOT gate motion (beam is hardware-gated).
- Machine identity from OCOTP nvmem: serial 00000000 → hostname XXX-XXX (matches the factory label).
Next work (in rough order)
- Backend milestone 2 — motion quality: motion is loud/jerky at the
10 kHz tick. Raise
GFSINK_RATEto 20–50 kHz (finer step-timing quantization), find factory-true run currents (puls-file headers carry them — see gfutilities settings map XSrc/YSrc) and sane accel/max-rate; verify smooth diagonal moves and feed-hold mid-move. - Laser mapping (gated on the scope session): spindle → power bytes (bit 7) + bit 4 laser-enable, M3/M4/$32 semantics, PWM-reset rule per the contract. No live fire before the standing scope gates: LASER_PWM waveform vs factory capture + ≤1-tick laser drop at underrun.
- Homing: X/Y home switch GPIOs exist in the cnc pin map (unused so far); wire as grblHAL limits or keep StallGuard-less factory scheme; Z homes against the hall sensor (top).
- 6.5 safety mapping: door/estop evdev → feed-hold/halt in the backend; underrun → grblHAL alarm; interlock-trip recovery check.
- 6.6 camera service: persistent MJPEG (ulfius, forgectrl) — also the natural time for the deferred 5.6 emulator smoke (homing images).
- Housekeeping: upstream the settings-write crash fix (grblHAL
crashes on every runtime $-settings write — NULL chained
grbl.on_settings_changedin gcode.c's gc_init); Phase 7 doc sweep (CLAUDE.md charter refresh, README roadmap); kas flip + first GitHub release per kas/README.md once ready to publish.