stm32: add H5 support.

13 files changed, 615 insertions, 0 deletions

diff --git a/examples/stm32h5/.cargo/config.toml b/examples/stm32h5/.cargo/config.toml
new file mode 100644
index 000000000..c8b864b6c
--- /dev/null
+++ b/examples/stm32h5/.cargo/config.toml
@@ -0,0 +1,8 @@
+[target.thumbv8m.main-none-eabihf]
+runner = 'probe-rs-cli run --chip STM32H563ZITx'
+
+[build]
+target = "thumbv8m.main-none-eabihf"
+
+[env]
+DEFMT_LOG = "trace"
diff --git a/examples/stm32h5/Cargo.toml b/examples/stm32h5/Cargo.toml
new file mode 100644
index 000000000..70702863f
--- /dev/null
+++ b/examples/stm32h5/Cargo.toml
@@ -0,0 +1,71 @@
+[package]
+edition = "2021"
+name = "embassy-stm32h7-examples"
+version = "0.1.0"
+license = "MIT OR Apache-2.0"
+
+[dependencies]
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
+embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["arch-cortex-m", "executor-thread", "defmt", "integrated-timers"] }
+embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "unstable-traits", "tick-hz-32_768"] }
+embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["nightly", "defmt", "stm32h563zi", "time-driver-any", "exti", "unstable-pac", "unstable-traits"] }
+embassy-net = { path = "../../embassy-net", features = ["defmt", "nightly", "tcp", "dhcpv4", "medium-ethernet", "unstable-traits", "proto-ipv6"] }
+embedded-io = { version = "0.4.0", features = ["async"] }
+embassy-usb = { version = "0.1.0", path = "../../embassy-usb", features = ["defmt"] }
+
+defmt = "0.3"
+defmt-rtt = "0.4"
+
+cortex-m = { version = "0.7.6", features = ["critical-section-single-core"] }
+cortex-m-rt = "0.7.0"
+embedded-hal = "0.2.6"
+embedded-hal-1 = { package = "embedded-hal", version = "=1.0.0-alpha.9" }
+embedded-hal-async = { version = "=0.2.0-alpha.0" }
+embedded-nal-async = "0.4.0"
+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 }
+rand_core = "0.6.3"
+critical-section = "1.1"
+micromath = "2.0.0"
+stm32-fmc = "0.2.4"
+embedded-storage = "0.3.0"
+static_cell = "1.0"
+
+# cargo build/run
+[profile.dev]
+codegen-units = 1
+debug = 2
+debug-assertions = true # <-
+incremental = false
+opt-level = 3 # <-
+overflow-checks = true # <-
+
+# cargo test
+[profile.test]
+codegen-units = 1
+debug = 2
+debug-assertions = true # <-
+incremental = false
+opt-level = 3 # <-
+overflow-checks = true # <-
+
+# cargo build/run --release
+[profile.release]
+codegen-units = 1
+debug = 2
+debug-assertions = false # <-
+incremental = false
+lto = 'fat'
+opt-level = 3 # <-
+overflow-checks = false # <-
+
+# cargo test --release
+[profile.bench]
+codegen-units = 1
+debug = 2
+debug-assertions = false # <-
+incremental = false
+lto = 'fat'
+opt-level = 3 # <-
+overflow-checks = false # <-
diff --git a/examples/stm32h5/build.rs b/examples/stm32h5/build.rs
new file mode 100644
index 000000000..8cd32d7ed
--- /dev/null
+++ b/examples/stm32h5/build.rs
@@ -0,0 +1,5 @@
+fn main() {
+    println!("cargo:rustc-link-arg-bins=--nmagic");
+    println!("cargo:rustc-link-arg-bins=-Tlink.x");
+    println!("cargo:rustc-link-arg-bins=-Tdefmt.x");
+}
diff --git a/examples/stm32h5/memory.x b/examples/stm32h5/memory.x
new file mode 100644
index 000000000..456061509
--- /dev/null
+++ b/examples/stm32h5/memory.x
@@ -0,0 +1,5 @@
+MEMORY
+{
+    FLASH : ORIGIN = 0x08000000, LENGTH = 0x200000
+    RAM   : ORIGIN = 0x20000000, LENGTH =  0x50000
+}
diff --git a/examples/stm32h5/src/bin/blinky.rs b/examples/stm32h5/src/bin/blinky.rs
new file mode 100644
index 000000000..f9bf90d2e
--- /dev/null
+++ b/examples/stm32h5/src/bin/blinky.rs
@@ -0,0 +1,27 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::gpio::{Level, Output, Speed};
+use embassy_time::{Duration, Timer};
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let p = embassy_stm32::init(Default::default());
+    info!("Hello World!");
+
+    let mut led = Output::new(p.PB0, Level::High, Speed::Low);
+
+    loop {
+        info!("high");
+        led.set_high();
+        Timer::after(Duration::from_millis(500)).await;
+
+        info!("low");
+        led.set_low();
+        Timer::after(Duration::from_millis(500)).await;
+    }
+}
diff --git a/examples/stm32h5/src/bin/button_exti.rs b/examples/stm32h5/src/bin/button_exti.rs
new file mode 100644
index 000000000..dfe587d41
--- /dev/null
+++ b/examples/stm32h5/src/bin/button_exti.rs
@@ -0,0 +1,27 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::exti::ExtiInput;
+use embassy_stm32::gpio::{Input, Pull};
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let p = embassy_stm32::init(Default::default());
+    info!("Hello World!");
+
+    let button = Input::new(p.PC13, Pull::Down);
+    let mut button = ExtiInput::new(button, p.EXTI13);
+
+    info!("Press the USER button...");
+
+    loop {
+        button.wait_for_rising_edge().await;
+        info!("Pressed!");
+        button.wait_for_falling_edge().await;
+        info!("Released!");
+    }
+}
diff --git a/examples/stm32h5/src/bin/eth.rs b/examples/stm32h5/src/bin/eth.rs
new file mode 100644
index 000000000..6d650da9e
--- /dev/null
+++ b/examples/stm32h5/src/bin/eth.rs
@@ -0,0 +1,133 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_net::tcp::TcpSocket;
+use embassy_net::{Ipv4Address, Stack, StackResources};
+use embassy_stm32::eth::generic_smi::GenericSMI;
+use embassy_stm32::eth::{Ethernet, PacketQueue};
+use embassy_stm32::peripherals::ETH;
+use embassy_stm32::rcc::{AHBPrescaler, APBPrescaler, Hse, HseMode, Pll, PllSource, Sysclk, VoltageScale};
+use embassy_stm32::rng::Rng;
+use embassy_stm32::time::Hertz;
+use embassy_stm32::{interrupt, Config};
+use embassy_time::{Duration, Timer};
+use embedded_io::asynch::Write;
+use rand_core::RngCore;
+use static_cell::StaticCell;
+use {defmt_rtt as _, panic_probe as _};
+
+macro_rules! singleton {
+    ($val:expr) => {{
+        type T = impl Sized;
+        static STATIC_CELL: StaticCell<T> = StaticCell::new();
+        let (x,) = STATIC_CELL.init(($val,));
+        x
+    }};
+}
+
+type Device = Ethernet<'static, ETH, GenericSMI>;
+
+#[embassy_executor::task]
+async fn net_task(stack: &'static Stack<Device>) -> ! {
+    stack.run().await
+}
+
+#[embassy_executor::main]
+async fn main(spawner: Spawner) -> ! {
+    let mut config = Config::default();
+    config.rcc.hsi = None;
+    config.rcc.hsi48 = true; // needed for rng
+    config.rcc.hse = Some(Hse {
+        freq: Hertz(8_000_000),
+        mode: HseMode::BypassDigital,
+    });
+    config.rcc.pll1 = Some(Pll {
+        source: PllSource::Hse,
+        prediv: 2,
+        mul: 125,
+        divp: Some(2),
+        divq: Some(2),
+        divr: None,
+    });
+    config.rcc.ahb_pre = AHBPrescaler::NotDivided;
+    config.rcc.apb1_pre = APBPrescaler::NotDivided;
+    config.rcc.apb2_pre = APBPrescaler::NotDivided;
+    config.rcc.apb3_pre = APBPrescaler::NotDivided;
+    config.rcc.sys = Sysclk::Pll1P;
+    config.rcc.voltage_scale = VoltageScale::Scale0;
+    let p = embassy_stm32::init(config);
+    info!("Hello World!");
+
+    // Generate random seed.
+    let mut rng = Rng::new(p.RNG);
+    let mut seed = [0; 8];
+    rng.fill_bytes(&mut seed);
+    let seed = u64::from_le_bytes(seed);
+
+    let eth_int = interrupt::take!(ETH);
+    let mac_addr = [0x00, 0x00, 0xDE, 0xAD, 0xBE, 0xEF];
+
+    let device = Ethernet::new(
+        singleton!(PacketQueue::<4, 4>::new()),
+        p.ETH,
+        eth_int,
+        p.PA1,
+        p.PA2,
+        p.PC1,
+        p.PA7,
+        p.PC4,
+        p.PC5,
+        p.PG13,
+        p.PB15,
+        p.PG11,
+        GenericSMI,
+        mac_addr,
+        0,
+    );
+
+    let config = embassy_net::Config::Dhcp(Default::default());
+    //let config = embassy_net::Config::Static(embassy_net::StaticConfig {
+    //    address: Ipv4Cidr::new(Ipv4Address::new(10, 42, 0, 61), 24),
+    //    dns_servers: Vec::new(),
+    //    gateway: Some(Ipv4Address::new(10, 42, 0, 1)),
+    //});
+
+    // Init network stack
+    let stack = &*singleton!(Stack::new(device, config, singleton!(StackResources::<2>::new()), seed));
+
+    // Launch network task
+    unwrap!(spawner.spawn(net_task(&stack)));
+
+    info!("Network task initialized");
+
+    // Then we can use it!
+    let mut rx_buffer = [0; 1024];
+    let mut tx_buffer = [0; 1024];
+
+    loop {
+        let mut socket = TcpSocket::new(&stack, &mut rx_buffer, &mut tx_buffer);
+
+        socket.set_timeout(Some(embassy_net::SmolDuration::from_secs(10)));
+
+        let remote_endpoint = (Ipv4Address::new(10, 42, 0, 1), 8000);
+        info!("connecting...");
+        let r = socket.connect(remote_endpoint).await;
+        if let Err(e) = r {
+            info!("connect error: {:?}", e);
+            Timer::after(Duration::from_secs(3)).await;
+            continue;
+        }
+        info!("connected!");
+        loop {
+            let r = socket.write_all(b"Hello\n").await;
+            if let Err(e) = r {
+                info!("write error: {:?}", e);
+                continue;
+            }
+            Timer::after(Duration::from_secs(1)).await;
+        }
+    }
+}
diff --git a/examples/stm32h5/src/bin/i2c.rs b/examples/stm32h5/src/bin/i2c.rs
new file mode 100644
index 000000000..6cbf58bbc
--- /dev/null
+++ b/examples/stm32h5/src/bin/i2c.rs
@@ -0,0 +1,44 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::i2c::{Error, I2c, TimeoutI2c};
+use embassy_stm32::interrupt;
+use embassy_stm32::time::Hertz;
+use embassy_time::Duration;
+use {defmt_rtt as _, panic_probe as _};
+
+const ADDRESS: u8 = 0x5F;
+const WHOAMI: u8 = 0x0F;
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    info!("Hello world!");
+    let p = embassy_stm32::init(Default::default());
+
+    let irq = interrupt::take!(I2C2_EV);
+    let mut i2c = I2c::new(
+        p.I2C2,
+        p.PB10,
+        p.PB11,
+        irq,
+        p.GPDMA1_CH4,
+        p.GPDMA1_CH5,
+        Hertz(100_000),
+        Default::default(),
+    );
+
+    // I2C bus can freeze if SCL line is shorted or due to a broken device that clock stretches for too long.
+    // TimeoutI2c allows recovering from such errors by throwing `Error::Timeout` after a given delay.
+    let mut timeout_i2c = TimeoutI2c::new(&mut i2c, Duration::from_millis(1000));
+
+    let mut data = [0u8; 1];
+
+    match timeout_i2c.blocking_write_read(ADDRESS, &[WHOAMI], &mut data) {
+        Ok(()) => info!("Whoami: {}", data[0]),
+        Err(Error::Timeout) => error!("Operation timed out"),
+        Err(e) => error!("I2c Error: {:?}", e),
+    }
+}
diff --git a/examples/stm32h5/src/bin/rng.rs b/examples/stm32h5/src/bin/rng.rs
new file mode 100644
index 000000000..af9be0b62
--- /dev/null
+++ b/examples/stm32h5/src/bin/rng.rs
@@ -0,0 +1,20 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::rng::Rng;
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let p = embassy_stm32::init(Default::default());
+    info!("Hello World!");
+
+    let mut rng = Rng::new(p.RNG);
+
+    let mut buf = [0u8; 16];
+    unwrap!(rng.async_fill_bytes(&mut buf).await);
+    info!("random bytes: {:02x}", buf);
+}
diff --git a/examples/stm32h5/src/bin/usart.rs b/examples/stm32h5/src/bin/usart.rs
new file mode 100644
index 000000000..405f18ec7
--- /dev/null
+++ b/examples/stm32h5/src/bin/usart.rs
@@ -0,0 +1,43 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use cortex_m_rt::entry;
+use defmt::*;
+use embassy_executor::Executor;
+use embassy_stm32::dma::NoDma;
+use embassy_stm32::interrupt;
+use embassy_stm32::usart::{Config, Uart};
+use static_cell::StaticCell;
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::task]
+async fn main_task() {
+    let p = embassy_stm32::init(Default::default());
+
+    let config = Config::default();
+    let irq = interrupt::take!(UART7);
+    let mut usart = Uart::new(p.UART7, p.PF6, p.PF7, irq, NoDma, NoDma, config);
+
+    unwrap!(usart.blocking_write(b"Hello Embassy World!\r\n"));
+    info!("wrote Hello, starting echo");
+
+    let mut buf = [0u8; 1];
+    loop {
+        unwrap!(usart.blocking_read(&mut buf));
+        unwrap!(usart.blocking_write(&buf));
+    }
+}
+
+static EXECUTOR: StaticCell<Executor> = StaticCell::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let executor = EXECUTOR.init(Executor::new());
+
+    executor.run(|spawner| {
+        unwrap!(spawner.spawn(main_task()));
+    })
+}
diff --git a/examples/stm32h5/src/bin/usart_dma.rs b/examples/stm32h5/src/bin/usart_dma.rs
new file mode 100644
index 000000000..43d791aae
--- /dev/null
+++ b/examples/stm32h5/src/bin/usart_dma.rs
@@ -0,0 +1,46 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use core::fmt::Write;
+
+use cortex_m_rt::entry;
+use defmt::*;
+use embassy_executor::Executor;
+use embassy_stm32::dma::NoDma;
+use embassy_stm32::interrupt;
+use embassy_stm32::usart::{Config, Uart};
+use heapless::String;
+use static_cell::StaticCell;
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::task]
+async fn main_task() {
+    let p = embassy_stm32::init(Default::default());
+
+    let config = Config::default();
+    let irq = interrupt::take!(UART7);
+    let mut usart = Uart::new(p.UART7, p.PF6, p.PF7, irq, p.GPDMA1_CH0, NoDma, config);
+
+    for n in 0u32.. {
+        let mut s: String<128> = String::new();
+        core::write!(&mut s, "Hello DMA World {}!\r\n", n).unwrap();
+
+        usart.write(s.as_bytes()).await.ok();
+
+        info!("wrote DMA");
+    }
+}
+
+static EXECUTOR: StaticCell<Executor> = StaticCell::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let executor = EXECUTOR.init(Executor::new());
+
+    executor.run(|spawner| {
+        unwrap!(spawner.spawn(main_task()));
+    })
+}
diff --git a/examples/stm32h5/src/bin/usart_split.rs b/examples/stm32h5/src/bin/usart_split.rs
new file mode 100644
index 000000000..16a499582
--- /dev/null
+++ b/examples/stm32h5/src/bin/usart_split.rs
@@ -0,0 +1,58 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::dma::NoDma;
+use embassy_stm32::interrupt;
+use embassy_stm32::peripherals::{GPDMA1_CH1, UART7};
+use embassy_stm32::usart::{Config, Uart, UartRx};
+use embassy_sync::blocking_mutex::raw::ThreadModeRawMutex;
+use embassy_sync::channel::Channel;
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::task]
+async fn writer(mut usart: Uart<'static, UART7, NoDma, NoDma>) {
+    unwrap!(usart.blocking_write(b"Hello Embassy World!\r\n"));
+    info!("wrote Hello, starting echo");
+
+    let mut buf = [0u8; 1];
+    loop {
+        unwrap!(usart.blocking_read(&mut buf));
+        unwrap!(usart.blocking_write(&buf));
+    }
+}
+
+static CHANNEL: Channel<ThreadModeRawMutex, [u8; 8], 1> = Channel::new();
+
+#[embassy_executor::main]
+async fn main(spawner: Spawner) -> ! {
+    let p = embassy_stm32::init(Default::default());
+    info!("Hello World!");
+
+    let config = Config::default();
+    let irq = interrupt::take!(UART7);
+    let mut usart = Uart::new(p.UART7, p.PF6, p.PF7, irq, p.GPDMA1_CH0, p.GPDMA1_CH1, config);
+    unwrap!(usart.blocking_write(b"Type 8 chars to echo!\r\n"));
+
+    let (mut tx, rx) = usart.split();
+
+    unwrap!(spawner.spawn(reader(rx)));
+
+    loop {
+        let buf = CHANNEL.recv().await;
+        info!("writing...");
+        unwrap!(tx.write(&buf).await);
+    }
+}
+
+#[embassy_executor::task]
+async fn reader(mut rx: UartRx<'static, UART7, GPDMA1_CH1>) {
+    let mut buf = [0; 8];
+    loop {
+        info!("reading...");
+        unwrap!(rx.read(&mut buf).await);
+        CHANNEL.send(buf).await;
+    }
+}
diff --git a/examples/stm32h5/src/bin/usb_serial.rs b/examples/stm32h5/src/bin/usb_serial.rs
new file mode 100644
index 000000000..6af269c1d
--- /dev/null
+++ b/examples/stm32h5/src/bin/usb_serial.rs
@@ -0,0 +1,128 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::{panic, *};
+use embassy_executor::Spawner;
+use embassy_stm32::rcc::{AHBPrescaler, APBPrescaler, Hse, HseMode, Pll, PllSource, Sysclk, VoltageScale};
+use embassy_stm32::time::Hertz;
+use embassy_stm32::usb::{Driver, Instance};
+use embassy_stm32::{interrupt, pac, Config};
+use embassy_usb::class::cdc_acm::{CdcAcmClass, State};
+use embassy_usb::driver::EndpointError;
+use embassy_usb::Builder;
+use futures::future::join;
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let mut config = Config::default();
+    config.rcc.hsi = None;
+    config.rcc.hsi48 = true; // needed for usb
+    config.rcc.hse = Some(Hse {
+        freq: Hertz(8_000_000),
+        mode: HseMode::BypassDigital,
+    });
+    config.rcc.pll1 = Some(Pll {
+        source: PllSource::Hse,
+        prediv: 2,
+        mul: 125,
+        divp: Some(2), // 250mhz
+        divq: None,
+        divr: None,
+    });
+    config.rcc.ahb_pre = AHBPrescaler::Div2;
+    config.rcc.apb1_pre = APBPrescaler::Div4;
+    config.rcc.apb2_pre = APBPrescaler::Div2;
+    config.rcc.apb3_pre = APBPrescaler::Div4;
+    config.rcc.sys = Sysclk::Pll1P;
+    config.rcc.voltage_scale = VoltageScale::Scale0;
+    let p = embassy_stm32::init(config);
+
+    info!("Hello World!");
+
+    unsafe {
+        pac::RCC.ccipr4().write(|w| {
+            w.set_usbsel(pac::rcc::vals::Usbsel::HSI48);
+        });
+    }
+
+    // Create the driver, from the HAL.
+    let irq = interrupt::take!(USB_DRD_FS);
+    let driver = Driver::new(p.USB, irq, p.PA12, p.PA11);
+
+    // Create embassy-usb Config
+    let mut config = embassy_usb::Config::new(0xc0de, 0xcafe);
+    config.manufacturer = Some("Embassy");
+    config.product = Some("USB-serial example");
+    config.serial_number = Some("12345678");
+
+    // Required for windows compatiblity.
+    // https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.9.1/kconfig/CONFIG_CDC_ACM_IAD.html#help
+    config.device_class = 0xEF;
+    config.device_sub_class = 0x02;
+    config.device_protocol = 0x01;
+    config.composite_with_iads = true;
+
+    // Create embassy-usb DeviceBuilder using the driver and config.
+    // It needs some buffers for building the descriptors.
+    let mut device_descriptor = [0; 256];
+    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 device_descriptor,
+        &mut config_descriptor,
+        &mut bos_descriptor,
+        &mut control_buf,
+    );
+
+    // Create classes on the builder.
+    let mut class = CdcAcmClass::new(&mut builder, &mut state, 64);
+
+    // Build the builder.
+    let mut usb = builder.build();
+
+    // Run the USB device.
+    let usb_fut = usb.run();
+
+    // Do stuff with the class!
+    let echo_fut = async {
+        loop {
+            class.wait_connection().await;
+            info!("Connected");
+            let _ = echo(&mut class).await;
+            info!("Disconnected");
+        }
+    };
+
+    // Run everything concurrently.
+    // If we had made everything `'static` above instead, we could do this using separate tasks instead.
+    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?;
+    }
+}