# pm-daisy — PolyMeter click engine on the Daisy Pod

A time-boxed spike (see [`docs/daisy-spike.md`](../../docs/daisy-spike.md)): play the PolyMeter
groove engine on real Cortex-M7 hardware to judge whether the [Electrosmith Daisy
Pod](https://electro-smith.com/products/pod) (STM32H750, onboard audio codec) is a credible home
for the audio engine if PolyMeter ever grows into a real-time audio workstation.

It boots playing a hardcoded 124-BPM 909 pattern (`pm_synth::SPIKE_PROGRAM`) out the Pod's audio
jack, flashing the Daisy Seed's USER LED on each click.

## What runs here
- **Shared engine, verified on host.** The audio is produced by `pm_synth::Player` — the *exact*
  same code the host `synthrender` renders to `pm-daisy-preview.wav`. Listen to that WAV to hear
  what the hardware should play before you flash anything.
- **Transport only is new.** This crate is a thin board-support binary: heap + board bring-up +
  the SAI audio-DMA interrupt feeding `Player::next_sample()` into stereo frames. Structure follows
  the `daisy` crate's `examples/audio.rs`.

## ⚠️ Set the board revision (or you get silence)
The Daisy Seed comes in revisions with different audio codecs. Pick the one on **your** Seed (check
the sticker / silkscreen) — it's a Cargo feature:

| Your Seed | Codec | Build with |
|---|---|---|
| Daisy Seed (original) | AK4556 | `./build.sh seed` |
| **Daisy Seed 1.1** (default) | WM8731 | `./build.sh` (or `seed_1_1`) |
| Daisy Seed 1.2 / Seed2 DFM | PCM3060 | `./build.sh seed_1_2` |

## Build
```sh
./build.sh [revision]     # containerized (pm-rust:2); produces pm-daisy.bin + pm-daisy.elf
```

## Flash — two options

**A. Debug probe (recommended — gives you defmt logs over RTT):**
A probe wired to the Seed's SWD pins (e.g. the Raspberry Pi Debug Probe you already use for
pm-grid/pm-kit — see [`rust/probe-flash.md`](../probe-flash.md)).
```sh
probe-rs run --chip STM32H750VBTx pm-daisy.elf    # or `cargo run --release` from this dir
```

**B. USB DFU (no probe needed):**
Hold the Daisy's **BOOT** button, tap **RESET**, release BOOT — the Seed enumerates as STM32 system
DFU. Then:
```sh
dfu-util -a 0 -s 0x08000000:leave -D pm-daisy.bin -d ,0483:df11
```

## Too big for 128 KB?
The STM32H750 has only **128 KB internal flash**. If the linker reports a `FLASH` overflow, flash via
the **Daisy Bootloader** to the 8 MB QSPI instead:
1. Install the bootloader once at <https://flash.daisy.audio/> (Bootloader tab, v6.x).
2. In [`memory.x`](memory.x), set `FLASH : ORIGIN = 0x90040000, LENGTH = 8M - 0x40000` (commented there).
3. Rebuild, then enter the bootloader (tap BOOT within 2 s of reset; LED pulses) and:
   ```sh
   dfu-util -a 0 -s 0x90040000:leave -D pm-daisy.bin -d ,0483:df11
   ```

## Pod controls
The Pod's buttons, encoder, knobs, and RGB LEDs are wired up (in `src/controls.rs` + `src/leds.rs`).
Boot still plays the spike groove (program index 0), so the original spike criteria stay observable.

| Control | Action |
|---|---|
| Encoder turn | tempo ±1 BPM per detent (clamped 5–300) |
| Encoder push | play / pause (ignored if you turned while holding it) |
| Button 1 / Button 2 | previous / next program (`src/programs.rs`, wraps) |
| Knob 1 | master volume (read at boot — no startup jump) |
| Knob 2 | reserved (read but unused) |
| RGB LED 1 | beat flash, colored by dynamic: accent = yellow, normal = cyan, ghost = magenta |
| RGB LED 2 | transport: green = playing, red = paused |
| Seed USER LED | unchanged spike beat flash |

At boot both RGB LEDs cycle R → G → B (a ~0.45 s self-test) so a miswired or dead leg is obvious
before audio starts. A live tempo or program change rebuilds the engine in the main loop (not the
audio IRQ) and swaps it in under a short critical section, preserving loop phase on tempo changes.

**Pin map** (verified against libDaisy `daisy_pod.cpp`, cross-checked with the `daisy` crate's
`pins.rs`): buttons D27/D28 (PG9/PA2), encoder A/B/click D26/D25/D13 (PD11/PA0/PB6), knobs D21/D15
(PC4/PC0 → ADC1), LED 1 D20/D19/D18 (PC1/PA6/PA7), LED 2 D17/D24/D23 (PB1/PA1/PA4). The RGB LEDs are
common-anode (active-low). If the encoder feels reversed or double-steps, adjust the decode in
`Pod::poll` (detents-per-quadrature-cycle varies by encoder).