WIP

Cargo.lock

@@ -828,6 +828,14 @@ dependencies = [
  "embedded-io-async",
 ]
 
+[[package]]
+name = "embedded-audio"
+version = "0.1.0"
+source = "git+https://github.com/LegitCamper/embedded-audio#087784644d810b94dd659a03dbed4795dfb0bd24"
+dependencies = [
+ "heapless",
+]
+
 [[package]]
 name = "embedded-graphics"
 version = "0.8.1"
@@ -1343,6 +1351,7 @@ dependencies = [
  "goblin",
  "heapless",
  "kolibri-embedded-gui",
+ "micromath",
  "num_enum 0.7.4",
  "once_cell",
  "panic-probe",
@@ -2516,6 +2525,16 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "wav_player"
+version = "0.1.0"
+dependencies = [
+ "abi",
+ "embedded-audio",
+ "embedded-graphics",
+ "rand",
+]
+
 [[package]]
 name = "winapi"
 version = "0.3.9"

Cargo.toml

@@ -7,6 +7,7 @@ members = [
   "user-apps/calculator",
   "user-apps/snake",
   "user-apps/gallery",
+  "user-apps/wav_player",
 ]
 
 [profile.release]

abi/src/lib.rs

@@ -1,7 +1,10 @@
 #![no_std]
 
+pub use abi_sys::{
+    AUDIO_BUFFER_LEN, audio_buffer_ready, file_len, get_key, list_dir, lock_display, print,
+    read_file, send_audio_buffer, sleep,
+};
 use abi_sys::{RngRequest, draw_iter, gen_rand};
-pub use abi_sys::{file_len, get_key, list_dir, lock_display, print, read_file, sleep};
 use rand_core::RngCore;
 pub use shared::keyboard::{KeyCode, KeyEvent, KeyState, Modifiers};
 use talc::*;

abi_sys/src/lib.rs

@@ -31,6 +31,8 @@ pub enum CallAbiTable {
     ListDir = 6,
     ReadFile = 7,
     FileLen = 8,
+    AudioBufferReady = 9,
+    SendAudioBuffer = 10,
 }
 
 pub type PrintAbi = extern "C" fn(ptr: *const u8, len: usize);
@@ -145,3 +147,27 @@ pub fn file_len(file: &str) -> usize {
         f(file.as_ptr(), file.len())
     }
 }
+
+pub type AudioBufferReady = extern "C" fn() -> bool;
+
+#[allow(unused)]
+pub fn audio_buffer_ready() -> bool {
+    unsafe {
+        let ptr = CALL_ABI_TABLE[CallAbiTable::AudioBufferReady as usize];
+        let f: AudioBufferReady = core::mem::transmute(ptr);
+        f()
+    }
+}
+
+pub const AUDIO_BUFFER_LEN: usize = 1024;
+
+pub type SendAudioBuffer = extern "C" fn(ptr: *const u8, len: usize);
+
+#[allow(unused)]
+pub fn send_audio_buffer(buf: &[u8; AUDIO_BUFFER_LEN]) {
+    unsafe {
+        let ptr = CALL_ABI_TABLE[CallAbiTable::SendAudioBuffer as usize];
+        let f: SendAudioBuffer = core::mem::transmute(ptr);
+        f(buf.as_ptr(), buf.len())
+    }
+}

justfile

@@ -13,3 +13,4 @@ userapps:
     just userapp calculator
     just userapp snake
     just userapp gallery
+    just userapp wav_player

kernel/Cargo.toml

@@ -94,3 +94,4 @@ bumpalo = "3.19.0"
 
 shared = { path = "../shared" }
 abi_sys = { path = "../abi_sys" }
+micromath = "2.1.0"

kernel/src/abi.rs

@@ -1,16 +1,17 @@
 use abi_sys::{
-    DrawIterAbi, FileLen, GenRand, GetKeyAbi, ListDir, LockDisplay, Modifiers, PrintAbi, ReadFile,
-    RngRequest, SleepAbi,
+    AUDIO_BUFFER_LEN, AudioBufferReady, DrawIterAbi, FileLen, GenRand, GetKeyAbi, ListDir,
+    LockDisplay, Modifiers, PrintAbi, ReadFile, RngRequest, SendAudioBuffer, SleepAbi,
 };
 use alloc::{string::ToString, vec::Vec};
 use core::sync::atomic::Ordering;
 use embassy_rp::clocks::{RoscRng, clk_sys_freq};
 use embedded_graphics::{Pixel, draw_target::DrawTarget, pixelcolor::Rgb565};
-use embedded_sdmmc::{DirEntry, LfnBuffer, ShortFileName};
+use embedded_sdmmc::{DirEntry, LfnBuffer};
 use heapless::spsc::Queue;
 use shared::keyboard::KeyEvent;
 
 use crate::{
+    audio::{AUDIO_BUFFER, AUDIO_BUFFER_READY},
     display::{FB_PAUSED, FRAMEBUFFER},
     storage::{Dir, File, SDCARD},
 };
@@ -181,7 +182,9 @@ pub extern "C" fn read_file(
     if !file.is_empty() {
         sd.access_root_dir(|root| {
             if let Ok(result) = recurse_file(&root, &file[1..], |file| {
-                file.seek_from_start(start_from as u32).unwrap();
+                if file.offset() as usize != start_from {
+                    file.seek_from_start(start_from as u32).unwrap();
+                }
                 file.read(&mut buf).unwrap()
             }) {
                 read = result
@@ -210,3 +213,21 @@ pub extern "C" fn file_len(str: *const u8, len: usize) -> usize {
     }
     len as usize
 }
+
+const _: AudioBufferReady = audio_buffer_ready;
+pub extern "C" fn audio_buffer_ready() -> bool {
+    AUDIO_BUFFER_READY.load(Ordering::Acquire)
+}
+
+const _: SendAudioBuffer = send_audio_buffer;
+pub extern "C" fn send_audio_buffer(ptr: *const u8, len: usize) {
+    // SAFETY: caller guarantees `ptr` is valid for `len` bytes
+    let buf = unsafe { core::slice::from_raw_parts(ptr, len) };
+
+    while !AUDIO_BUFFER_READY.load(Ordering::Acquire) {}
+
+    if buf.len() == AUDIO_BUFFER_LEN {
+        unsafe { AUDIO_BUFFER.copy_from_slice(buf) };
+        AUDIO_BUFFER_READY.store(false, Ordering::Release)
+    }
+}

kernel/src/audio.rs

@@ -0,0 +1,52 @@
+use core::{
+    sync::atomic::{AtomicBool, Ordering},
+    time::Duration,
+};
+use embassy_rp::{
+    Peri,
+    pio::Pio,
+    pio_programs::pwm::{PioPwm, PioPwmProgram},
+    pwm::{Config, Pwm, SetDutyCycle},
+};
+use embassy_time::Timer;
+
+use crate::{Audio, Irqs};
+
+const AUDIO_BUFFER_LEN: usize = 1024;
+const _: () = assert!(AUDIO_BUFFER_LEN == abi_sys::AUDIO_BUFFER_LEN);
+pub static mut AUDIO_BUFFER: [u8; AUDIO_BUFFER_LEN] = [0; AUDIO_BUFFER_LEN];
+static mut AUDIO_BUFFER_1: [u8; AUDIO_BUFFER_LEN] = [0; AUDIO_BUFFER_LEN];
+
+pub static AUDIO_BUFFER_READY: AtomicBool = AtomicBool::new(true);
+
+pub const SAMPLE_RATE_HZ: u32 = 22_050;
+
+#[embassy_executor::task]
+pub async fn audio_handler(audio: Audio) {
+    let var_name = Pio::new(audio.pio_left, Irqs);
+    let Pio {
+        mut common, sm0, ..
+    } = var_name;
+
+    let prg = PioPwmProgram::new(&mut common);
+    let mut pwm_pio = PioPwm::new(&mut common, sm0, audio.left, &prg);
+
+    let period = Duration::from_nanos(1_000_000_000 / SAMPLE_RATE_HZ as u64);
+    pwm_pio.set_period(period);
+
+    pwm_pio.start();
+
+    let sample_interval = 1_000_000 / SAMPLE_RATE_HZ as u64; // in µs ≈ 45 µs
+
+    loop {
+        for &sample in unsafe { &AUDIO_BUFFER }.iter() {
+            let period_ns = period.as_nanos() as u32;
+            let duty_ns = period_ns * (sample as u32) / 255;
+            pwm_pio.write(Duration::from_nanos(duty_ns as u64));
+            Timer::after_micros(sample_interval).await; // sample interval = 1 / sample rate
+        }
+
+        unsafe { core::mem::swap(&mut AUDIO_BUFFER, &mut AUDIO_BUFFER_1) };
+        AUDIO_BUFFER_READY.store(true, Ordering::Release)
+    }
+}

kernel/src/elf.rs

@@ -204,6 +204,8 @@ fn patch_abi(
                             CallAbiTable::ListDir => abi::list_dir as usize,
                             CallAbiTable::ReadFile => abi::read_file as usize,
                             CallAbiTable::FileLen => abi::file_len as usize,
+                            CallAbiTable::AudioBufferReady => abi::audio_buffer_ready as usize,
+                            CallAbiTable::SendAudioBuffer => abi::send_audio_buffer as usize,
                         };
                         unsafe {
                             table_base.add(idx as usize).write(ptr);

kernel/src/main.rs

@@ -7,6 +7,7 @@
 extern crate alloc;
 
 mod abi;
+mod audio;
 mod display;
 mod elf;
 mod framebuffer;
@@ -19,6 +20,7 @@ mod utils;
 
 use crate::{
     abi::KEY_CACHE,
+    audio::audio_handler,
     display::{FRAMEBUFFER, display_handler, init_display},
     peripherals::{
         conf_peripherals,
@@ -48,8 +50,10 @@ use embassy_rp::{
     multicore::{Stack, spawn_core1},
     peripherals::{
         DMA_CH0, DMA_CH1, I2C1, PIN_6, PIN_7, PIN_10, PIN_11, PIN_12, PIN_13, PIN_14, PIN_15,
-        PIN_16, PIN_17, PIN_18, PIN_19, PIN_22, SPI0, SPI1, USB,
+        PIN_16, PIN_17, PIN_18, PIN_19, PIN_22, PIN_26, PIN_27, PIO0, PIO1, PWM_SLICE5, SPI0, SPI1,
+        USB,
     },
+    pio,
     spi::{self, Spi},
     usb as embassy_rp_usb,
 };
@@ -65,6 +69,7 @@ use talc::*;
 embassy_rp::bind_interrupts!(struct Irqs {
     I2C1_IRQ => i2c::InterruptHandler<I2C1>;
     USBCTRL_IRQ => embassy_rp_usb::InterruptHandler<USB>;
+    PIO0_IRQ_0 => pio::InterruptHandler<PIO0>;
 });
 
 static mut CORE1_STACK: Stack<16384> = Stack::new();
@@ -105,6 +110,12 @@ async fn main(_spawner: Spawner) {
         data: p.PIN_14,
         reset: p.PIN_15,
     };
+    let audio = Audio {
+        pio_left: p.PIO0,
+        pio_right: p.PIO1,
+        left: p.PIN_26,
+        right: p.PIN_27,
+    };
     let sd = Sd {
         spi: p.SPI0,
         clk: p.PIN_18,
@@ -119,7 +130,9 @@ async fn main(_spawner: Spawner) {
         data: p.PIN_6,
     };
     let executor0 = EXECUTOR0.init(Executor::new());
-    executor0.run(|spawner| unwrap!(spawner.spawn(kernel_task(spawner, display, sd, mcu, p.USB))));
+    executor0.run(|spawner| {
+        unwrap!(spawner.spawn(kernel_task(spawner, display, audio, sd, mcu, p.USB)))
+    });
 }
 
 // One-slot channel to pass EntryFn from core1
@@ -168,6 +181,12 @@ struct Display {
     data: Peri<'static, PIN_14>,
     reset: Peri<'static, PIN_15>,
 }
+struct Audio {
+    pio_left: Peri<'static, PIO0>,
+    pio_right: Peri<'static, PIO1>,
+    left: Peri<'static, PIN_26>,
+    right: Peri<'static, PIN_27>,
+}
 struct Sd {
     spi: Peri<'static, SPI0>,
     clk: Peri<'static, PIN_18>,
@@ -225,6 +244,7 @@ async fn setup_sd(sd: Sd) {
 async fn kernel_task(
     spawner: Spawner,
     display: Display,
+    audio: Audio,
     sd: Sd,
     mcu: Mcu,
     usb: Peri<'static, USB>,
@@ -234,6 +254,8 @@ async fn kernel_task(
     setup_display(display, spawner).await;
     setup_sd(sd).await;
 
+    spawner.spawn(audio_handler(audio)).unwrap();
+
     let _usb = embassy_rp_usb::Driver::new(usb, Irqs);
     // spawner.spawn(usb_handler(usb)).unwrap();
 

user-apps/wav_player/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "wav_player"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+abi = { path = "../../abi" }
+embedded-graphics = "0.8.1"
+rand = { version = "0.9.0", default-features = false }
+embedded-audio = { git = "https://github.com/LegitCamper/embedded-audio" }

user-apps/wav_player/build.rs

@@ -0,0 +1,28 @@
+//! This build script copies the `memory.x` file from the crate root into
+//! a directory where the linker can always find it at build time.
+//! For many projects this is optional, as the linker always searches the
+//! project root directory -- wherever `Cargo.toml` is. However, if you
+//! are using a workspace or have a more complicated build setup, this
+//! build script becomes required. Additionally, by requesting that
+//! Cargo re-run the build script whenever `memory.x` is changed,
+//! updating `memory.x` ensures a rebuild of the application with the
+//! new memory settings.
+
+use std::env;
+use std::fs::File;
+use std::io::Write;
+use std::path::PathBuf;
+
+fn main() {
+    // Put `memory.x` in our output directory and ensure it's
+    // on the linker search path.
+    let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
+    File::create(out.join("memory.x"))
+        .unwrap()
+        .write_all(include_bytes!("../memory.x"))
+        .unwrap();
+    println!("cargo:rustc-link-search={}", out.display());
+
+    println!("cargo:rerun-if-changed=memory.x");
+    println!("cargo:rustc-link-arg-bins=-Tmemory.x");
+}

user-apps/wav_player/src/main.rs

@@ -0,0 +1,92 @@
+#![no_std]
+#![no_main]
+
+extern crate alloc;
+use abi::{
+    AUDIO_BUFFER_LEN, KeyCode, KeyState, Rng, audio_buffer_ready,
+    display::{Display, SCREEN_HEIGHT, SCREEN_WIDTH},
+    file_len, get_key, lock_display, print, read_file, send_audio_buffer, sleep,
+};
+use alloc::{format, string::String};
+use core::panic::PanicInfo;
+use embedded_audio::{AudioFile, PlatformFile, PlatformFileError, wav::Wav};
+use embedded_graphics::{pixelcolor::Rgb565, prelude::RgbColor};
+
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    print(&format!(
+        "user panic: {} @ {:?}",
+        info.message(),
+        info.location(),
+    ));
+    loop {}
+}
+
+#[unsafe(no_mangle)]
+pub extern "Rust" fn _start() {
+    main()
+}
+
+pub fn main() {
+    print("Starting Wav player app");
+    let mut display = Display;
+
+    let mut buf = [0_u8; AUDIO_BUFFER_LEN];
+
+    let file = File::new(String::from("/music/test.wav"));
+    let mut wav = Wav::new(file).unwrap();
+    loop {
+        if audio_buffer_ready() {
+            if wav.is_eof() {
+                wav.restart().unwrap()
+            }
+
+            wav.read(&mut buf).unwrap();
+            send_audio_buffer(&buf);
+        }
+    }
+}
+
+struct File {
+    current_pos: usize,
+    file: String,
+}
+
+impl File {
+    fn new(file: String) -> Self {
+        Self {
+            current_pos: 0,
+            file,
+        }
+    }
+}
+
+impl PlatformFile for File {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize, PlatformFileError> {
+        let read = read_file(&self.file, self.current_pos, buf);
+        Ok(read)
+    }
+
+    fn seek_from_current(&mut self, offset: i64) -> Result<(), PlatformFileError> {
+        if offset.is_positive() {
+            self.current_pos += offset as usize;
+        } else {
+            self.current_pos -= offset as usize;
+        }
+        Ok(())
+    }
+
+    fn seek_from_start(&mut self, offset: usize) -> Result<(), PlatformFileError> {
+        self.current_pos = offset;
+        Ok(())
+    }
+
+    fn seek_from_end(&mut self, offset: usize) -> Result<(), PlatformFileError> {
+        self.current_pos = self.length() - offset;
+        Ok(())
+    }
+
+    fn length(&mut self) -> usize {
+        file_len(&self.file)
+    }
+}