eecea625d3
A new, first-actually-buildable form factor for the 52Pi EP-0172 "Pico Breadboard
Kit Plus" (Raspberry Pi Pico; 3.5" ST7796 320x480 cap-touch via GT911, PSP
joystick on ADC0/1, WS2812 RGB on GP12, buzzer GP13, buttons GP14/15):
- pico/main.py — one self-contained MicroPython file: ST7796 direct-draw driver,
GT911 touch (16-bit register addressing), WS2812 RGB (neopixel), PWM buzzer,
ADC joystick, buttons. It parses the project's own program-string language
(verified against the web engine's semantics) and runs a non-blocking
ticks_us scheduler with an on-screen touch UI. CONFIG flags cover panel /
colour / touch / joystick calibration. pico/README.md has flashing +
calibration steps.
- kit.html — lean widget that mirrors the firmware's on-screen UI (portrait
320x480 canvas) plus a joystick / RGB / buzzer / A-B buttons; plays via the
shared engine. info-kit.html — the real EP-0172 pinout, a parts list
(~$45 incl. Pico) and the firmware to flash (downloads /pico-main.py, links
the README + source).
- Landing + embed page list the Kit; build.sh/deploy.sh build the two pages and
serve pico/main.py as /pico-main.py for download.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
76 lines
4 KiB
Markdown
76 lines
4 KiB
Markdown
# PM_K‑1 "Kit" — VARASYS PolyMeter firmware for the Raspberry Pi Pico
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MicroPython firmware that turns a **Raspberry Pi Pico** on the **52Pi EP‑0172 "Pico
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Breadboard Kit Plus"** into a touchscreen polymeter metronome. It runs the *same program
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strings* as <https://metronome.varasys.io> — design a groove in the web editor, copy its
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program string, paste it into `PROGRAMS` in `main.py`, and it plays here.
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Everything is in one file: `main.py` (ST7796 display driver, GT911 touch, WS2812 RGB,
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buzzer, joystick, the polymeter engine — no external libraries).
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## The board (EP‑0172) — fixed pinout
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| Component | Pico pins |
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|---|---|
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| 3.5″ ST7796 320×480 display | SPI0 — SCK `GP2`, MOSI `GP3`, CS `GP5`, DC `GP6`, RST `GP7` |
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| GT911 capacitive touch | I2C0 — SDA `GP8`, SCL `GP9` (addr 0x5D) |
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| WS2812 RGB LED | `GP12` |
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| Buzzer | `GP13` |
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| Button A / Button B | `GP15` / `GP14` |
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| PSP joystick | X = `ADC0`/`GP26`, Y = `ADC1`/`GP27` |
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The components are wired on the board — you don't breadboard anything; just seat the Pico.
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## Flash it
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1. **MicroPython:** hold **BOOTSEL**, plug the Pico into USB, and copy the MicroPython UF2
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onto the `RPI-RP2` drive that appears:
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- Pico / Pico W → <https://micropython.org/download/RPI_PICO/>
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- Pico 2 / Pico 2 W → <https://micropython.org/download/RPI_PICO2/>
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2. **The firmware:** open `main.py` in [Thonny](https://thonny.org) (or `rshell`/`mpremote`)
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and save it to the Pico **as `main.py`**.
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- Thonny: open the file → **File ▸ Save as… ▸ Raspberry Pi Pico** → name it `main.py`.
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- mpremote: `mpremote cp main.py :main.py`
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3. Reset (replug). It boots straight into the metronome.
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## Controls
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- **Touch:** on‑screen `<<` / `>||` / `>>` (prev · play/stop · next) and `−` / `TAP` / `+`.
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- **Joystick:** up/down = tempo (push far for ±5), left/right = previous/next groove.
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- **Button A (GP15):** play / stop. **Button B (GP14):** tap tempo.
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- **RGB LED** flashes each beat (amber = accent, cyan = normal, violet = ghost); the
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**buzzer** clicks with matching pitch.
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## Add your own grooves
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Edit the `PROGRAMS` list near the top of `main.py` — each entry is `("Name", "program string")`.
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Get program strings from the web editor's program box (e.g. `v1;t120;kick:4;snare:4=.X.X;hat:4/2`).
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Supported: tempo `t<bpm>`, lanes `sound:grouping[/sub][=pattern][~][!]`, pattern chars
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`X` accent · `x` normal · `g` ghost · `.` `-` `_` rest, grouped meters like `3+3+2`, polymeter `~`.
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(Per‑lane dB gain `@n` is parsed but ignored — the buzzer is mono.)
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## If something looks off — calibration
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All the knobs are flags in the `CONFIG` block at the top of `main.py`:
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- **Colours look negative / washed out:** toggle `INVERT_COLORS`.
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- **Red and blue swapped:** set `SWAP_RB = True`.
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- **Taps land in the wrong place:** set `TOUCH_DEBUG = True`, reset, watch the raw
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coordinates over the USB serial (Thonny shell) as you tap the corners, then set
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`TOUCH_SWAP_XY` / `TOUCH_INVERT_X` / `TOUCH_INVERT_Y` to match.
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- **Joystick reversed:** toggle `JOY_INVERT_X` / `JOY_INVERT_Y`; widen `JOY_DEADZONE` if it drifts.
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- **Screen stays black:** the backlight is hardwired on, so this usually means the SPI init
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didn't take — drop `SPI_BAUD` to `24_000_000` and retry.
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- **Garbled / wrong size image:** your panel lot may be a 240×320 ILI9341 instead of the
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320×480 ST7796. This firmware targets the ST7796 you have (you said 320×480); if a unit
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ever ships ILI9341, set `WIDTH,HEIGHT = 240,320` and use an ILI9341 init sequence.
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## Notes
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- Audio is a single passive buzzer, so coincident lane hits play one click at the highest
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priority (accent > normal > ghost); the RGB + screen still show the combined activity.
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- The scheduler is non‑blocking and timed off `time.ticks_us()`, so tempo stays steady while
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the screen and inputs update.
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Hardware reference: [52Pi EP‑0172 wiki](https://wiki.52pi.com/index.php?title=EP-0172) ·
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[vendor code](https://github.com/geeekpi/pico_breakboard_kit). VARASYS — Simplifying Complexity.
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