Add stm32 USB OTG peripherals

examples/stm32f4/Cargo.toml

@@ -8,7 +8,7 @@ resolver = "2"
 
 [dependencies]
 embassy = { version = "0.1.0", path = "../../embassy", features = ["defmt", "unstable-traits"] }
-embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["defmt", "stm32f429zi", "unstable-pac", "memory-x", "time-driver-any", "exti"]  }
+embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["defmt", "stm32f429zi", "unstable-pac", "memory-x", "time-driver-any", "exti", "usb-otg-fs"]  }
 
 defmt = "0.3"
 defmt-rtt = "0.3"
@@ -20,3 +20,6 @@ panic-probe = { version = "0.3", features = ["print-defmt"] }
 futures = { version = "0.3.17", default-features = false, features = ["async-await"] }
 heapless = { version = "0.7.5", default-features = false }
 nb = "1.0.0"
+
+usb-device = "0.2"
+usbd-serial = "0.1.1"

examples/stm32f4/src/bin/usb_uart.rs

@@ -0,0 +1,99 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+
+use defmt::{info, unwrap};
+use defmt_rtt as _; // global logger
+use embassy::interrupt::InterruptExt;
+use futures::pin_mut;
+use panic_probe as _; // print out panic messages
+
+use embassy::executor::Spawner;
+use embassy::io::{AsyncBufReadExt, AsyncWriteExt};
+use embassy_stm32::usb_otg_fs::{State, Usb, UsbBus, UsbOtgFs, UsbSerial};
+use embassy_stm32::{interrupt, time::Hertz, Config, Peripherals};
+use usb_device::device::{UsbDeviceBuilder, UsbVidPid};
+
+static mut EP_MEMORY: [u32; 2048] = [0; 2048];
+
+// USB requires at least 48 MHz clock
+fn config() -> Config {
+    let mut config = Config::default();
+    config.rcc.sys_ck = Some(Hertz(48_000_000));
+    config
+}
+
+#[embassy::main(config = "config()")]
+async fn main(_spawner: Spawner, p: Peripherals) {
+    let mut rx_buffer = [0u8; 64];
+    // we send back input + cr + lf
+    let mut tx_buffer = [0u8; 66];
+
+    let peri = UsbOtgFs::new(p.USB_OTG_FS, p.PA12, p.PA11);
+    let usb_bus = UsbBus::new(peri, unsafe { &mut EP_MEMORY });
+
+    let serial = UsbSerial::new(&usb_bus, &mut rx_buffer, &mut tx_buffer);
+
+    let device = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0x16c0, 0x27dd))
+        .manufacturer("Fake company")
+        .product("Serial port")
+        .serial_number("TEST")
+        .device_class(0x02)
+        .build();
+
+    let irq = interrupt::take!(OTG_FS);
+    irq.set_priority(interrupt::Priority::P3);
+
+    let mut state = State::new();
+    let usb = unsafe { Usb::new(&mut state, device, serial, irq) };
+    pin_mut!(usb);
+
+    let (mut reader, mut writer) = usb.as_ref().take_serial_0();
+
+    info!("usb initialized!");
+
+    unwrap!(
+        writer
+            .write_all(b"\r\nInput returned upper cased on CR+LF\r\n")
+            .await
+    );
+
+    let mut buf = [0u8; 64];
+    loop {
+        let mut n = 0;
+
+        async {
+            loop {
+                let char = unwrap!(reader.read_byte().await);
+
+                if char == b'\r' || char == b'\n' {
+                    break;
+                }
+
+                buf[n] = char;
+                n += 1;
+
+                // stop if we're out of room
+                if n == buf.len() {
+                    break;
+                }
+            }
+        }
+        .await;
+
+        if n > 0 {
+            for char in buf[..n].iter_mut() {
+                // upper case
+                if 0x61 <= *char && *char <= 0x7a {
+                    *char &= !0x20;
+                }
+            }
+            unwrap!(writer.write_all(&buf[..n]).await);
+            unwrap!(writer.write_all(b"\r\n").await);
+            unwrap!(writer.flush().await);
+        }
+    }
+}