WIP: Audio out using the CS43L22 DAC

Author: maxekman

.vscode/launch.json

@@ -29,15 +29,16 @@
       "cwd": "${workspaceRoot}",
       "preLaunchTask": "cargo build --examples",
       "runToMain": true,
-      "executable": "./target/thumbv7em-none-eabihf/debug/{{project-name}}",
+      // "executable": "./target/thumbv7em-none-eabihf/debug/{{project-name}}",
       /* Run `cargo build --example itm` and uncomment this line to run itm example */
       // "executable": "./target/thumbv7em-none-eabihf/debug/examples/itm",
+      "executable": "./target/thumbv7em-none-eabihf/debug/examples/audio",
       "device": "STM32F407VGT6",
       "configFiles": ["openocd.cfg"],
       "svdFile": "${workspaceRoot}/.vscode/STM32F407.svd",
       "swoConfig": {
         "enabled": true,
-        "cpuFrequency": 16000000,
+        "cpuFrequency": 168000000,
         "swoFrequency": 2000000,
         "source": "probe",
         "decoders": [{ "type": "console", "label": "ITM", "port": 0 }]

Cargo.toml

@@ -24,18 +24,32 @@ cortex-m = "0.6"
 cortex-m-rt = "0.6"
 lis302dl = "0.1.0"
 
+[dependencies.cs43l22]
+# git = "https://github.com/maxekman/cs43l22/"
+# branch = "master"
+path = "../cs43l22"
+
 [dependencies.embedded-hal]
+# TODO: Update version when I2S proposal is finalized:
+# https://github.com/rust-embedded/embedded-hal/pull/204
 features = ["unproven"]
-version = "0.2"
+# version = "0.2.3"
+# git = "https://github.com/eldruin/embedded-hal/"
+# branch = "i2s"
+path = "../embedded-hal"
 
 [dependencies.stm32f4xx-hal]
 default-features = false
 features = ["rt", "stm32f407"]
-version = "0.8.2"
+# version = "0.8.2"
+# git = "https://github.com/maxekman/stm32f4xx-hal/"
+# branch = "i2s"
+path = "../stm32f4xx-hal"
 
 [dev-dependencies]
 ssd1306 = "0.2"
 nb = "0.1"
+cortex-m-log = { version = "~0.6", features = ["itm"] }
 panic-halt = "0.2"
 panic-itm = "0.4"
 

examples/audio.rs

@@ -0,0 +1,68 @@
+//! Plays a test tone through the DAC with headphone amp.
+
+#![no_main]
+#![no_std]
+
+extern crate panic_itm;
+
+use cortex_m::peripheral::Peripherals;
+use cortex_m_rt::entry;
+
+use stm32f407g_disc as board;
+
+use crate::board::{audio_out::AudioOut, hal::delay::Delay, hal::prelude::*, hal::stm32};
+
+use cortex_m_log::println;
+use cortex_m_log::{destination::Itm, printer::itm::InterruptSync as InterruptSyncItm};
+
+#[entry]
+fn main() -> ! {
+    let p = stm32::Peripherals::take().unwrap();
+    let cp = Peripherals::take().unwrap();
+
+    let mut log = InterruptSyncItm::new(Itm::new(cp.ITM));
+
+    let gpioa = p.GPIOA.split();
+    let gpiob = p.GPIOB.split();
+    let gpioc = p.GPIOC.split();
+    let gpiod = p.GPIOD.split();
+
+    // TODO: Use frequency when setting up clocks.
+    let audio_freq = 48000;
+
+    // Set clock to 64 MHz and freeze.
+    let rcc = p.RCC.constrain();
+    let clocks = rcc
+        .cfgr
+        .use_hse(8.mhz())
+        .sysclk(168.mhz())
+        .plli2sclk(audio_freq.hz())
+        .freeze();
+
+    // Get delay provider.
+    let mut delay = Delay::new(cp.SYST, clocks);
+
+    println!(log, "\nSetup audio output");
+    let mut audio_out = AudioOut::new(
+        p.I2C1, p.SPI3, gpioa, gpiob, gpioc, gpiod, clocks, &mut delay, audio_freq, 128,
+    );
+
+    println!(log, "Starting audio");
+    let mut s: u16 = 0;
+    let mut y: u16 = 100;
+    loop {
+        // Send both left and right word.
+        audio_out.i2s.send(s).unwrap();
+        audio_out.i2s.send(s).unwrap();
+
+        // Sawtooth with incrementing pitch each cycle.
+        if s >= (65535 - y) {
+            s = 0;
+            y += 1;
+            if y > 400 {
+                y = 100
+            }
+        }
+        s += y;
+    }
+}

openocd.gdb

@@ -20,8 +20,13 @@ break main
 monitor tpiu config internal itm.txt uart off 168000000
 
 
-# OR: make the microcontroller SWO (PB3) pin output compatible with UART (8N1)
-# 8000000 is the frequency of the SWO pin
+# # send captured ITM to the file itm.fifo
+# # (the microcontroller SWO pin must be connected to the programmer SWO pin)
+# # 16000000 must match the core clock frequency
+monitor tpiu config internal itm.txt uart off 168000000
+
+# # OR: make the microcontroller SWO pin output compatible with UART (8N1)
+# # 8000000 is the frequency of the SWO pin
 # monitor tpiu config external uart off 8000000 2000000
 
 # # enable ITM port 1

src/audio_out.rs

@@ -0,0 +1,70 @@
+//! CS43L22 DAC with headphone amp.
+
+use crate::hal::prelude::*;
+
+use crate::hal::gpio::gpioa::{self, PA4};
+use crate::hal::gpio::gpiob::{self, PB6, PB9};
+use crate::hal::gpio::gpioc::{self, PC10, PC12};
+use crate::hal::gpio::gpiod::{self, PD4};
+use crate::hal::gpio::{Alternate, AlternateOD, Output, PushPull, AF4, AF6};
+use crate::hal::i2c::*;
+use crate::hal::i2s::*;
+use crate::hal::rcc::Clocks;
+use crate::hal::stm32::{I2C1, SPI3};
+
+use embedded_hal::blocking::delay::DelayMs;
+
+pub use cs43l22;
+
+pub struct AudioOut {
+    pub cs43l22: cs43l22::CS43L22<
+        I2c<I2C1, (PB6<AlternateOD<AF4>>, PB9<AlternateOD<AF4>>)>,
+        PD4<Output<PushPull>>,
+    >,
+    pub i2s: I2s<
+        SPI3,
+        (
+            PC10<Alternate<AF6>>,
+            PA4<Alternate<AF6>>,
+            PC12<Alternate<AF6>>,
+            NoSdExt,
+        ),
+    >,
+}
+
+impl AudioOut {
+    pub fn new<DELAY: DelayMs<u8>>(
+        i2c1: I2C1,
+        spi3: SPI3,
+        gpioa: gpioa::Parts,
+        gpiob: gpiob::Parts,
+        gpioc: gpioc::Parts,
+        gpiod: gpiod::Parts,
+        clocks: Clocks,
+        delay: &mut DELAY,
+        audio_freq: u32,
+        vol: u8,
+    ) -> Self {
+        // Setup I2C1 using PB6 and PB9 pins at 100kHz bitrate.
+        let scl = gpiob.pb6.into_alternate_af4().set_open_drain();
+        let sda = gpiob.pb9.into_alternate_af4().set_open_drain();
+        let i2c1 = I2c::i2c1(i2c1, (scl, sda), 100.khz(), clocks);
+
+        // CS43L22 reset pin.
+        let reset = gpiod.pd4.into_push_pull_output();
+
+        // Set PC7 into AF6 to output the MCLK for I2S3.
+        let _mck = gpioc.pc7.into_alternate_af6();
+
+        // Setup I2S3 for 48kHz audio.
+        let ck = gpioc.pc10.into_alternate_af6();
+        let ws = gpioa.pa4.into_alternate_af6();
+        let sd = gpioc.pc12.into_alternate_af6();
+        let i2s3 = I2s::i2s3(spi3, (ck, ws, sd, NoSdExt), audio_freq.hz(), clocks);
+
+        let cs43l22 = cs43l22::CS43L22::new(i2c1, reset, delay, vol)
+            .expect("could not create CS43L22 driver");
+
+        AudioOut { cs43l22, i2s: i2s3 }
+    }
+}

src/lib.rs

@@ -12,4 +12,5 @@ pub use cortex_m::*;
 pub use cortex_m_rt::*;
 
 pub mod accelerometer;
+pub mod audio_out;
 pub mod led;