implement basic piano

- scan
- configurable pins
- no velocity yet

src/bin/geode_piano.rs

@@ -0,0 +1,84 @@
+/*
+    geode-piano
+    Copyright (C) 2024 dogeystamp <dogeystamp@disroot.org>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+//! Main firmware for geode-piano. Reads key-matrix and sends MIDI output.
+
+#![no_std]
+#![no_main]
+#![deny(rust_2018_idioms)]
+
+use embassy_executor::Spawner;
+use embassy_rp::bind_interrupts;
+use embassy_rp::i2c;
+use embassy_rp::peripherals::USB;
+use embassy_rp::usb::{Driver, InterruptHandler};
+use geode_piano::usb::usb_task;
+use geode_piano::matrix::KeyMatrix;
+use geode_piano::{blinky, pin_array, pins, unwrap};
+
+#[embassy_executor::task]
+async fn piano_task(pin_driver: pins::TransparentPins) {
+    use geode_piano::midi::Note::*;
+
+    // GND pins
+    let col_pins = [23];
+    // Input pins
+    let row_pins = [20, 15, 4];
+    // Notes for each key
+    let keymap = [[C4, D4, E4]];
+
+    let mut mat = KeyMatrix::new(col_pins, row_pins, keymap);
+    mat.scan(pin_driver).await;
+}
+
+bind_interrupts!(struct Irqs {
+    USBCTRL_IRQ => InterruptHandler<USB>;
+});
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let p = embassy_rp::init(Default::default());
+
+    let driver = Driver::new(p.USB, Irqs);
+    unwrap(_spawner.spawn(usb_task(driver, log::LevelFilter::Debug))).await;
+    unwrap(_spawner.spawn(blinky::blink_task(p.PIN_25.into()))).await;
+
+    log::debug!("main: init i2c");
+    let sda = p.PIN_16;
+    let scl = p.PIN_17;
+
+    let mut i2c_config = i2c::Config::default();
+    let freq = 100_000;
+    i2c_config.frequency = freq;
+    let i2c = i2c::I2c::new_blocking(p.I2C0, scl, sda, i2c_config);
+
+    log::debug!("main: starting transparent pin driver");
+    let pin_driver = unwrap(pins::TransparentPins::new(
+        i2c,
+        [0x20, 0x27],
+        pin_array!(
+            p.PIN_15, p.PIN_14, p.PIN_13, p.PIN_12, p.PIN_11, p.PIN_10, p.PIN_9, p.PIN_18,
+            p.PIN_19, p.PIN_20, p.PIN_21, p.PIN_22
+        ),
+        true,
+    ))
+    .await;
+
+    log::info!("main: starting piano task");
+    _spawner.spawn(piano_task(pin_driver)).unwrap();
+}

src/lib.rs

@@ -12,6 +12,7 @@ pub mod blinky;
 pub mod midi;
 pub mod pins;
 pub mod usb;
+pub mod matrix;
 
 /// Unwrap, but log before panic
 ///

src/matrix.rs

@@ -0,0 +1,70 @@
+//! Key matrix scanner
+
+use crate::pins;
+use crate::midi;
+use crate::unwrap;
+use embassy_rp::gpio;
+use embassy_time::{Duration, Ticker};
+
+/// Key matrix for the piano.
+pub struct KeyMatrix<const N_ROWS: usize, const N_COLS: usize> {
+    /// GND pins at the top of each column
+    col_pins: [u8; N_COLS],
+    /// Input pins at the left of each row
+    row_pins: [u8; N_ROWS],
+    keymap: [[midi::Note; N_ROWS]; N_COLS],
+}
+
+impl<const N_ROWS: usize, const N_COLS: usize> KeyMatrix<N_ROWS, N_COLS> {
+    /// New function.
+    ///
+    /// `col_pins` are GND pins at the top of the columns, and `row_pins` are the input pins at
+    /// the ends of the rows.
+    ///
+    /// `keymap` represents the note that every combination of col/row gives.
+    pub fn new(
+        col_pins: [u8; N_COLS],
+        row_pins: [u8; N_ROWS],
+        keymap: [[midi::Note; N_ROWS]; N_COLS],
+    ) -> Self {
+        KeyMatrix {
+            col_pins,
+            row_pins,
+            keymap,
+        }
+    }
+
+    pub async fn scan(&mut self, mut pin_driver: pins::TransparentPins) {
+        for i in pin_driver.pins {
+            unwrap(pin_driver.set_input(i)).await;
+            unwrap(pin_driver.set_pull(i, gpio::Pull::Up)).await;
+        }
+        let mut ticker = Ticker::every(Duration::from_millis(10));
+        let chan = midi::MidiChannel::new(0);
+        let mut note_on = [false; 128];
+
+        loop {
+            for (i, col) in self.col_pins.iter().enumerate() {
+                unwrap(pin_driver.set_output(*col)).await;
+                let input = unwrap(pin_driver.read_all()).await;
+                unwrap(pin_driver.set_input(*col)).await;
+
+                // values that are logical ON
+                let mask = input ^ (((1 << pin_driver.n_usable_pins()) - 1) ^ (1 << col));
+                for (j, row) in self.row_pins.iter().enumerate() {
+                    let note = self.keymap[i][j];
+                    if mask & (1 << row) != 0 {
+                        if !note_on[note as usize] {
+                            note_on[note as usize] = true;
+                            chan.note_on(note, 40).await;
+                        }
+                    } else if note_on[note as usize] {
+                        note_on[note as usize] = false;
+                        chan.note_off(note, 0).await;
+                    }
+                }
+            }
+            ticker.next().await;
+        }
+    }
+}

src/midi/mod.rs

@@ -24,14 +24,20 @@ use embassy_rp::usb::{Driver, Instance};
 use embassy_sync::{blocking_mutex::raw::ThreadModeRawMutex, channel::Channel};
 use embassy_usb::{class::midi::MidiClass, driver::EndpointError};
 
+////////////////////////////////
+////////////////////////////////
+// MIDI message types
+////////////////////////////////
+////////////////////////////////
+
 struct NoteMsg {
     on: bool,
-    note: u8,
+    note: Note,
     velocity: u8,
 }
 
 impl NoteMsg {
-    fn new(on: bool, note: u8, velocity: u8) -> Self {
+    fn new(on: bool, note: Note, velocity: u8) -> Self {
         NoteMsg { on, note, velocity }
     }
 }
@@ -71,6 +77,118 @@ impl MidiMsg {
     }
 }
 
+////////////////////////////////
+////////////////////////////////
+// Public MIDI interface
+////////////////////////////////
+////////////////////////////////
+
+/// Note identifiers
+///
+/// See src/midi/note_def.py for how this is generated
+#[derive(Clone, Copy)]
+pub enum Note {
+    A0 = 21,
+    AS0 = 22,
+    B0 = 23,
+    C1 = 24,
+    CS1 = 25,
+    D1 = 26,
+    DS1 = 27,
+    E1 = 28,
+    F1 = 29,
+    FS1 = 30,
+    G1 = 31,
+    GS1 = 32,
+    A1 = 33,
+    AS1 = 34,
+    B1 = 35,
+    C2 = 36,
+    CS2 = 37,
+    D2 = 38,
+    DS2 = 39,
+    E2 = 40,
+    F2 = 41,
+    FS2 = 42,
+    G2 = 43,
+    GS2 = 44,
+    A2 = 45,
+    AS2 = 46,
+    B2 = 47,
+    C3 = 48,
+    CS3 = 49,
+    D3 = 50,
+    DS3 = 51,
+    E3 = 52,
+    F3 = 53,
+    FS3 = 54,
+    G3 = 55,
+    GS3 = 56,
+    A3 = 57,
+    AS3 = 58,
+    B3 = 59,
+    C4 = 60,
+    CS4 = 61,
+    D4 = 62,
+    DS4 = 63,
+    E4 = 64,
+    F4 = 65,
+    FS4 = 66,
+    G4 = 67,
+    GS4 = 68,
+    A4 = 69,
+    AS4 = 70,
+    B4 = 71,
+    C5 = 72,
+    CS5 = 73,
+    D5 = 74,
+    DS5 = 75,
+    E5 = 76,
+    F5 = 77,
+    FS5 = 78,
+    G5 = 79,
+    GS5 = 80,
+    A5 = 81,
+    AS5 = 82,
+    B5 = 83,
+    C6 = 84,
+    CS6 = 85,
+    D6 = 86,
+    DS6 = 87,
+    E6 = 88,
+    F6 = 89,
+    FS6 = 90,
+    G6 = 91,
+    GS6 = 92,
+    A6 = 93,
+    AS6 = 94,
+    B6 = 95,
+    C7 = 96,
+    CS7 = 97,
+    D7 = 98,
+    DS7 = 99,
+    E7 = 100,
+    F7 = 101,
+    FS7 = 102,
+    G7 = 103,
+    GS7 = 104,
+    A7 = 105,
+    AS7 = 106,
+    B7 = 107,
+    C8 = 108,
+    CS8 = 109,
+    D8 = 110,
+    DS8 = 111,
+    E8 = 112,
+    F8 = 113,
+    FS8 = 114,
+    G8 = 115,
+    GS8 = 116,
+    A8 = 117,
+    AS8 = 118,
+    B8 = 119,
+}
+
 pub struct Disconnected {}
 
 impl From<EndpointError> for Disconnected {
@@ -94,14 +212,14 @@ pub async fn midi_session<'d, T: Instance + 'd>(
             MsgType::Note(note) => {
                 let status: u8 = (if note.on { 0b1001_0000 } else { 0b1000_0000 }) | msg.channel;
                 // i'll be honest i have no idea where the first number here comes from
-                let packet = [8, status, note.note, note.velocity];
-                log::debug!("midi_session: note {:?}", packet);
+                let packet = [8, status, note.note as u8, note.velocity];
+                log::trace!("midi_session: note {:?}", packet);
                 midi.write_packet(&packet).await?
             }
             MsgType::Controller(ctrl) => {
                 let status: u8 = (0b1011_0000) | msg.channel;
                 let packet = [8, status, ctrl.controller as u8, ctrl.value];
-                log::debug!("midi_session: control {:?}", packet);
+                log::trace!("midi_session: control {:?}", packet);
                 midi.write_packet(&packet).await?
             }
         }
@@ -119,7 +237,7 @@ impl MidiChannel {
     }
 
     /// MIDI Note-On
-    pub async fn note_on(&self, note: u8, velocity: u8) {
+    pub async fn note_on(&self, note: Note, velocity: u8) {
         MIDI_QUEUE
             .send(MidiMsg::new(
                 MsgType::Note(NoteMsg::new(true, note, velocity)),
@@ -129,7 +247,7 @@ impl MidiChannel {
     }
 
     /// MIDI Note-Off
-    pub async fn note_off(&self, note: u8, velocity: u8) {
+    pub async fn note_off(&self, note: Note, velocity: u8) {
         MIDI_QUEUE
             .send(MidiMsg::new(
                 MsgType::Note(NoteMsg::new(false, note, velocity)),

src/midi/note_def.py

@@ -0,0 +1,15 @@
+#!/usr/bin/env python3
+
+"""Generates the MIDI `Note` enum based on https://gist.github.com/dimitre/439f5ab75a0c2e66c8c63fc9e8f7ea77."""
+
+import csv
+
+with open("note_freq_440_432.csv") as f:
+    reader = csv.reader(f)
+    for row in reader:
+        note_code: int = int(row[0])
+        note_name: str = row[1]
+        octave: int = int(row[2])
+
+        identifier = f"{note_name.replace('#', 'S')}{octave}"
+        print(f"{identifier} = {note_code},")