Merge pull request #4623 from paroga/stm32l0_usb_serial

stm32/l0: Add usb serial example

examples/stm32l0/Cargo.toml

@@ -11,6 +11,8 @@ embassy-stm32 = { version = "0.4.0", path = "../../embassy-stm32", features = ["
 embassy-sync = { version = "0.7.2", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.9.0", path = "../../embassy-executor", features = ["arch-cortex-m", "executor-thread", "defmt"] }
 embassy-time = { version = "0.5.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-hz-32_768"] }
+embassy-usb = { version = "0.5.1", path = "../../embassy-usb", features = ["defmt"] }
+embassy-futures = { version = "0.1.2", path = "../../embassy-futures" }
 
 defmt = "1.0.1"
 defmt-rtt = "1.0.0"

examples/stm32l0/src/bin/usb_serial.rs

@@ -0,0 +1,95 @@
+#![no_std]
+#![no_main]
+
+use defmt::{panic, *};
+use embassy_executor::Spawner;
+use embassy_futures::join::join;
+use embassy_stm32::usb::{self, Driver, Instance};
+use embassy_stm32::{bind_interrupts, peripherals};
+use embassy_usb::class::cdc_acm::{CdcAcmClass, State};
+use embassy_usb::driver::EndpointError;
+use embassy_usb::Builder;
+use {defmt_rtt as _, panic_probe as _};
+
+bind_interrupts!(struct Irqs {
+    USB => usb::InterruptHandler<peripherals::USB>;
+});
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let mut config = embassy_stm32::Config::default();
+    {
+        use embassy_stm32::rcc::*;
+        config.rcc.hsi = true;
+        config.rcc.pll = Some(Pll {
+            source: PllSource::HSI,
+            mul: PllMul::MUL6, // PLLVCO = 16*6 = 96Mhz
+            div: PllDiv::DIV3, // 32Mhz clock (16 * 6 / 3)
+        });
+        config.rcc.sys = Sysclk::PLL1_R;
+    }
+
+    let p = embassy_stm32::init(config);
+
+    info!("Hello World!");
+
+    let driver = Driver::new(p.USB, Irqs, p.PA12, p.PA11);
+
+    let mut config = embassy_usb::Config::new(0xc0de, 0xcafe);
+    config.manufacturer = Some("Embassy");
+    config.product = Some("USB-Serial Example");
+    config.serial_number = Some("123456");
+
+    let mut config_descriptor = [0; 256];
+    let mut bos_descriptor = [0; 256];
+    let mut control_buf = [0; 64];
+
+    let mut state = State::new();
+
+    let mut builder = Builder::new(
+        driver,
+        config,
+        &mut config_descriptor,
+        &mut bos_descriptor,
+        &mut [], // no msos descriptors
+        &mut control_buf,
+    );
+
+    let mut class = CdcAcmClass::new(&mut builder, &mut state, 64);
+
+    let mut usb = builder.build();
+
+    let usb_fut = usb.run();
+
+    let echo_fut = async {
+        loop {
+            class.wait_connection().await;
+            info!("Connected");
+            let _ = echo(&mut class).await;
+            info!("Disconnected");
+        }
+    };
+
+    join(usb_fut, echo_fut).await;
+}
+
+struct Disconnected {}
+
+impl From<EndpointError> for Disconnected {
+    fn from(val: EndpointError) -> Self {
+        match val {
+            EndpointError::BufferOverflow => panic!("Buffer overflow"),
+            EndpointError::Disabled => Disconnected {},
+        }
+    }
+}
+
+async fn echo<'d, T: Instance + 'd>(class: &mut CdcAcmClass<'d, Driver<'d, T>>) -> Result<(), Disconnected> {
+    let mut buf = [0; 64];
+    loop {
+        let n = class.read_packet(&mut buf).await?;
+        let data = &buf[..n];
+        info!("data: {:x}", data);
+        class.write_packet(data).await?;
+    }
+}