Add USB driver

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Enabled commented out and now available GPIOE support for 07x and 09x families
 - Extract register block address only once
 - Add DAC driver
+- Added USB driver
 
 ## [v0.15.1] - 2019-08-11
 

Cargo.toml

@@ -37,9 +37,12 @@ embedded-hal = { version = "0.2", features = ["unproven"] }
 stm32f0 = "0.8"
 nb = "0.1"
 void = { version = "1.0", default-features = false }
+stm32-usbd = { version = "0.5.0", features = ["ram_access_2x16"], optional = true }
 
 [dev-dependencies]
 panic-halt = "0.2"
+usb-device = "0.2.3"
+usbd-serial = "0.1.0"
 
 [features]
 device-selected = []
@@ -80,3 +83,7 @@ required-features = ["stm32f042", "rt"]
 [[example]]
 name = "dac"
 required-features = ["stm32f072"]
+
+[[example]]
+name = "usb_serial"
+required-features = ["rt", "stm32f042", "stm32-usbd"]

examples/usb_serial.rs

@@ -0,0 +1,90 @@
+//! CDC-ACM serial port example using polling in a busy loop.
+//! Target board: NUCLEO-F042K6
+#![no_std]
+#![no_main]
+
+extern crate panic_halt;
+
+use cortex_m_rt::entry;
+use stm32f0xx_hal::usb::{Peripheral, UsbBus};
+use stm32f0xx_hal::{prelude::*, stm32};
+use usb_device::prelude::*;
+use usbd_serial::{SerialPort, USB_CLASS_CDC};
+
+#[entry]
+fn main() -> ! {
+    let mut dp = stm32::Peripherals::take().unwrap();
+
+    /* Uncomment the following lines if you have a chip in TSSOP20 (STM32F042F)
+       or UFQFPN28 (STM32F042G) package
+       This code enables clock for SYSCFG and remaps USB pins to PA9 and PA10.
+    */
+    //dp.RCC.apb2enr.modify(|_, w| w.syscfgen().set_bit());
+    //dp.SYSCFG.cfgr1.modify(|_, w| w.pa11_pa12_rmp().remapped());
+
+    let mut rcc = dp
+        .RCC
+        .configure()
+        .hsi48()
+        .enable_crs(dp.CRS)
+        .sysclk(48.mhz())
+        .pclk(24.mhz())
+        .freeze(&mut dp.FLASH);
+
+    // Configure the on-board LED (LD3, green)
+    let gpiob = dp.GPIOB.split(&mut rcc);
+    let mut led = cortex_m::interrupt::free(|cs| gpiob.pb3.into_push_pull_output(cs));
+    led.set_low(); // Turn off
+
+    let gpioa = dp.GPIOA.split(&mut rcc);
+
+    let usb = Peripheral {
+        usb: dp.USB,
+        pin_dm: gpioa.pa11,
+        pin_dp: gpioa.pa12,
+    };
+    let usb_bus = UsbBus::new(usb);
+
+    let mut serial = SerialPort::new(&usb_bus);
+
+    let mut usb_dev = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0x16c0, 0x27dd))
+        .manufacturer("Fake company")
+        .product("Serial port")
+        .serial_number("TEST")
+        .device_class(USB_CLASS_CDC)
+        .build();
+
+    loop {
+        if !usb_dev.poll(&mut [&mut serial]) {
+            continue;
+        }
+
+        let mut buf = [0u8; 64];
+
+        match serial.read(&mut buf) {
+            Ok(count) if count > 0 => {
+                led.set_high(); // Turn on
+
+                // Echo back in upper case
+                for c in buf[0..count].iter_mut() {
+                    if 0x61 <= *c && *c <= 0x7a {
+                        *c &= !0x20;
+                    }
+                }
+
+                let mut write_offset = 0;
+                while write_offset < count {
+                    match serial.write(&buf[write_offset..count]) {
+                        Ok(len) if len > 0 => {
+                            write_offset += len;
+                        }
+                        _ => {}
+                    }
+                }
+            }
+            _ => {}
+        }
+
+        led.set_low(); // Turn off
+    }
+}

src/lib.rs

@@ -69,5 +69,17 @@ pub mod timers;
     feature = "stm32f098",
 ))]
 pub mod tsc;
+#[cfg(all(
+    feature = "stm32-usbd",
+    any(
+        feature = "stm32f042",
+        feature = "stm32f048",
+        feature = "stm32f072",
+        feature = "stm32f078",
+        feature = "stm32f070x6",
+        feature = "stm32f070xb",
+    )
+))]
+pub mod usb;
 #[cfg(feature = "device-selected")]
 pub mod watchdog;

src/usb.rs

@@ -0,0 +1,44 @@
+//! USB peripheral
+
+use crate::stm32::{RCC, USB};
+use stm32_usbd::UsbPeripheral;
+
+use crate::gpio::gpioa::{PA11, PA12};
+use crate::gpio::{Floating, Input};
+pub use stm32_usbd::UsbBus;
+
+pub struct Peripheral {
+    pub usb: USB,
+    pub pin_dm: PA11<Input<Floating>>,
+    pub pin_dp: PA12<Input<Floating>>,
+}
+
+unsafe impl Sync for Peripheral {}
+
+unsafe impl UsbPeripheral for Peripheral {
+    const REGISTERS: *const () = USB::ptr() as *const ();
+    const DP_PULL_UP_FEATURE: bool = true;
+    const EP_MEMORY: *const () = 0x4000_6000 as _;
+    const EP_MEMORY_SIZE: usize = 1024;
+
+    fn enable() {
+        let rcc = unsafe { (&*RCC::ptr()) };
+
+        cortex_m::interrupt::free(|_| {
+            // Enable USB peripheral
+            rcc.apb1enr.modify(|_, w| w.usben().set_bit());
+
+            // Reset USB peripheral
+            rcc.apb1rstr.modify(|_, w| w.usbrst().set_bit());
+            rcc.apb1rstr.modify(|_, w| w.usbrst().clear_bit());
+        });
+    }
+
+    fn startup_delay() {
+        // There is a chip specific startup delay. For STM32F103xx it's 1µs and this should wait for
+        // at least that long.
+        cortex_m::asm::delay(72);
+    }
+}
+
+pub type UsbBusType = UsbBus<Peripheral>;