Merge pull request #2143 from adamgreig/raw-usb-example

Add raw USB example using control transfers

1 files changed, 201 insertions, 0 deletions

diff --git a/examples/stm32f4/src/bin/usb_raw.rs b/examples/stm32f4/src/bin/usb_raw.rs
new file mode 100644
index 000000000..8d4e6c7d6
--- /dev/null
+++ b/examples/stm32f4/src/bin/usb_raw.rs
@@ -0,0 +1,201 @@
+//! Example of using USB without a pre-defined class, but instead responding to
+//! raw USB control requests.
+//!
+//! The host computer can either:
+//! * send a command, with a 16-bit request ID, a 16-bit value, and an optional data buffer
+//! * request some data, with a 16-bit request ID, a 16-bit value, and a length of data to receive
+//!
+//! For higher throughput data, you can add some bulk endpoints after creating the alternate,
+//! but for low rate command/response, plain control transfers can be very simple and effective.
+//!
+//! Example code to send/receive data using `nusb`:
+//!
+//! ```ignore
+//! use futures_lite::future::block_on;
+//! use nusb::transfer::{ControlIn, ControlOut, ControlType, Recipient};
+//!
+//! fn main() {
+//!     let di = nusb::list_devices()
+//!         .unwrap()
+//!         .find(|d| d.vendor_id() == 0xc0de && d.product_id() == 0xcafe)
+//!         .expect("no device found");
+//!     let device = di.open().expect("error opening device");
+//!     let interface = device.claim_interface(0).expect("error claiming interface");
+//!
+//!     // Send "hello world" to device
+//!     let result = block_on(interface.control_out(ControlOut {
+//!         control_type: ControlType::Vendor,
+//!         recipient: Recipient::Interface,
+//!         request: 100,
+//!         value: 200,
+//!         index: 0,
+//!         data: b"hello world",
+//!     }));
+//!     println!("{result:?}");
+//!
+//!     // Receive "hello" from device
+//!     let result = block_on(interface.control_in(ControlIn {
+//!         control_type: ControlType::Vendor,
+//!         recipient: Recipient::Interface,
+//!         request: 101,
+//!         value: 201,
+//!         index: 0,
+//!         length: 5,
+//!     }));
+//!     println!("{result:?}");
+//! }
+//! ```
+
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::time::Hertz;
+use embassy_stm32::usb_otg::Driver;
+use embassy_stm32::{bind_interrupts, peripherals, usb_otg, Config};
+use embassy_usb::control::{InResponse, OutResponse, Recipient, Request, RequestType};
+use embassy_usb::types::InterfaceNumber;
+use embassy_usb::{Builder, Handler};
+use {defmt_rtt as _, panic_probe as _};
+
+bind_interrupts!(struct Irqs {
+    OTG_FS => usb_otg::InterruptHandler<peripherals::USB_OTG_FS>;
+});
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    info!("Hello World!");
+
+    let mut config = Config::default();
+    {
+        use embassy_stm32::rcc::*;
+        config.rcc.hse = Some(Hse {
+            freq: Hertz(8_000_000),
+            mode: HseMode::Bypass,
+        });
+        config.rcc.pll_src = PllSource::HSE;
+        config.rcc.pll = Some(Pll {
+            prediv: PllPreDiv::DIV4,
+            mul: PllMul::MUL168,
+            divp: Some(Pllp::DIV2), // 8mhz / 4 * 168 / 2 = 168Mhz.
+            divq: Some(Pllq::DIV7), // 8mhz / 4 * 168 / 7 = 48Mhz.
+            divr: None,
+        });
+        config.rcc.ahb_pre = AHBPrescaler::DIV1;
+        config.rcc.apb1_pre = APBPrescaler::DIV4;
+        config.rcc.apb2_pre = APBPrescaler::DIV2;
+        config.rcc.sys = Sysclk::PLL1_P;
+    }
+    let p = embassy_stm32::init(config);
+
+    // Create the driver, from the HAL.
+    let mut ep_out_buffer = [0u8; 256];
+    let mut config = embassy_stm32::usb_otg::Config::default();
+    config.vbus_detection = true;
+    let driver = Driver::new_fs(p.USB_OTG_FS, Irqs, p.PA12, p.PA11, &mut ep_out_buffer, config);
+
+    // Create embassy-usb Config
+    let mut config = embassy_usb::Config::new(0xc0de, 0xcafe);
+    config.manufacturer = Some("Embassy");
+    config.product = Some("USB-raw example");
+    config.serial_number = Some("12345678");
+
+    // Required for windows compatibility.
+    // 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 handler = ControlHandler {
+        if_num: InterfaceNumber(0),
+    };
+
+    let mut builder = Builder::new(
+        driver,
+        config,
+        &mut device_descriptor,
+        &mut config_descriptor,
+        &mut bos_descriptor,
+        &mut control_buf,
+    );
+
+    // Add a vendor-specific function (class 0xFF), and corresponding interface,
+    // that uses our custom handler.
+    let mut function = builder.function(0xFF, 0, 0);
+    let mut interface = function.interface();
+    let _alternate = interface.alt_setting(0xFF, 0, 0, None);
+    handler.if_num = interface.interface_number();
+    drop(function);
+    builder.handler(&mut handler);
+
+    // Build the builder.
+    let mut usb = builder.build();
+
+    // Run the USB device.
+    usb.run().await;
+}
+
+/// Handle CONTROL endpoint requests and responses. For many simple requests and responses
+/// you can get away with only using the control endpoint.
+struct ControlHandler {
+    if_num: InterfaceNumber,
+}
+
+impl Handler for ControlHandler {
+    /// Respond to HostToDevice control messages, where the host sends us a command and
+    /// optionally some data, and we can only acknowledge or reject it.
+    fn control_out<'a>(&'a mut self, req: Request, buf: &'a [u8]) -> Option<OutResponse> {
+        // Log the request before filtering to help with debugging.
+        info!("Got control_out, request={}, buf={:a}", req, buf);
+
+        // Only handle Vendor request types to an Interface.
+        if req.request_type != RequestType::Vendor || req.recipient != Recipient::Interface {
+            return None;
+        }
+
+        // Ignore requests to other interfaces.
+        if req.index != self.if_num.0 as u16 {
+            return None;
+        }
+
+        // Accept request 100, value 200, reject others.
+        if req.request == 100 && req.value == 200 {
+            Some(OutResponse::Accepted)
+        } else {
+            Some(OutResponse::Rejected)
+        }
+    }
+
+    /// Respond to DeviceToHost control messages, where the host requests some data from us.
+    fn control_in<'a>(&'a mut self, req: Request, buf: &'a mut [u8]) -> Option<InResponse<'a>> {
+        info!("Got control_in, request={}", req);
+
+        // Only handle Vendor request types to an Interface.
+        if req.request_type != RequestType::Vendor || req.recipient != Recipient::Interface {
+            return None;
+        }
+
+        // Ignore requests to other interfaces.
+        if req.index != self.if_num.0 as u16 {
+            return None;
+        }
+
+        // Respond "hello" to request 101, value 201, when asked for 5 bytes, otherwise reject.
+        if req.request == 101 && req.value == 201 && req.length == 5 {
+            buf[..5].copy_from_slice(b"hello");
+            Some(InResponse::Accepted(&buf[..5]))
+        } else {
+            Some(InResponse::Rejected)
+        }
+    }
+}