Add blok_usb_serial example

boards/boardsource-blok/Cargo.toml

@@ -13,17 +13,19 @@ repository = "https://github.com/rp-rs/rp-hal-boards.git"
 [dependencies]
 cortex-m = "0.7.7"
 rp2040-boot2 = { version = "0.3.0", optional = true}
-rp2040-hal = { version = "0.8.1"}
+rp2040-hal = { version = "0.8.2"}
 cortex-m-rt = { version = "0.7.3", optional = true}
 fugit = "0.3.5"
 
 [dev-dependencies]
 panic-halt = "0.2.0"
 embedded-hal = "0.2.7"
 nb = "1.0"
+heapless = "0.7.16"
 smart-leds = "0.3.0"
 ws2812-pio = "0.6.0"
 usb-device = "0.2.9"
+usbd-serial = "0.1.1"
 usbd-hid = "0.5.2"
 critical-section = "1.1.1"
 

boards/boardsource-blok/README.md

@@ -95,6 +95,12 @@ Resets the Blok after 10 seconds to usb boot mode.
 Demonstrates emulating a USB Human Input Device (HID) Keyboard. The keyboard
 will type "HELLO" five times.
 
+### [blok_usb_serial](./examples/blok_usb_serial.rs)
+
+Demonstrates creating a USB Serial device.
+The device will loop 10 times, where on each loop the current loop number is printed.
+If the device reads "stop", the blok will reset to usb boot mode.
+
 ## Contributing
 
 Contributions are what make the open source community such an amazing place to

boards/boardsource-blok/examples/blok_usb_serial.rs

@@ -0,0 +1,154 @@
+//! # USB Serial Example for the Blok
+//!
+//! Creates a USB Serial device on a blok board, with the USB driver running in
+//! the USB interrupt and all writes being done in the main loop with the usage
+//! of critical section.
+//!
+//! This will create a USB Serial device and then write to it.
+//! A loop will write its current loop number 10 times after which
+//! the Blok will reset to usb boot mode.
+//! If "stop" is read by the serial device, the Blok will also
+//! reset to usb boot mode.
+//!
+//! See the `Cargo.toml` file for Copyright and license details.
+
+#![no_std]
+#![no_main]
+
+use boardsource_blok::{entry, hal};
+use boardsource_blok::{
+    hal::{
+        clocks::{init_clocks_and_plls, Clock},
+        pac,
+        pac::interrupt,
+        timer::Timer,
+        watchdog::Watchdog,
+        Sio,
+    },
+    Pins, XOSC_CRYSTAL_FREQ,
+};
+use core::fmt::Write;
+use heapless::String;
+use panic_halt as _;
+use usb_device::{
+    bus::UsbBusAllocator, device::UsbDevice, device::UsbDeviceBuilder, device::UsbVidPid,
+};
+use usbd_serial::SerialPort;
+
+// shared with the interrupt
+static mut USB_DEVICE: Option<UsbDevice<hal::usb::UsbBus>> = None;
+static mut USB_BUS: Option<UsbBusAllocator<hal::usb::UsbBus>> = None;
+static mut USB_SERIAL: Option<SerialPort<hal::usb::UsbBus>> = None;
+
+#[entry]
+fn main() -> ! {
+    let mut pac = pac::Peripherals::take().unwrap();
+
+    let mut watchdog = Watchdog::new(pac.WATCHDOG);
+
+    let clocks = init_clocks_and_plls(
+        XOSC_CRYSTAL_FREQ,
+        pac.XOSC,
+        pac.CLOCKS,
+        pac.PLL_SYS,
+        pac.PLL_USB,
+        &mut pac.RESETS,
+        &mut watchdog,
+    )
+    .ok()
+    .unwrap();
+
+    let sio = Sio::new(pac.SIO);
+    let _pins = Pins::new(
+        pac.IO_BANK0,
+        pac.PADS_BANK0,
+        sio.gpio_bank0,
+        &mut pac.RESETS,
+    );
+
+    let _timer = Timer::new(pac.TIMER, &mut pac.RESETS);
+
+    let usb_bus = UsbBusAllocator::new(hal::usb::UsbBus::new(
+        pac.USBCTRL_REGS,
+        pac.USBCTRL_DPRAM,
+        clocks.usb_clock,
+        true,
+        &mut pac.RESETS,
+    ));
+    unsafe {
+        USB_BUS = Some(usb_bus);
+    }
+
+    let bus_ref = unsafe { USB_BUS.as_ref().unwrap() };
+
+    let serial = SerialPort::new(bus_ref);
+    unsafe {
+        USB_SERIAL = Some(serial);
+    }
+
+    let usb_device = UsbDeviceBuilder::new(bus_ref, UsbVidPid(0x1209, 0x0001))
+        .product("serial port")
+        .device_class(2) // from: https://www.usb.org/defined-class-codes
+        .build();
+    unsafe {
+        USB_DEVICE = Some(usb_device);
+    }
+
+    unsafe {
+        pac::NVIC::unmask(hal::pac::Interrupt::USBCTRL_IRQ);
+    }
+
+    let core = pac::CorePeripherals::take().unwrap();
+    let mut delay = cortex_m::delay::Delay::new(core.SYST, clocks.system_clock.freq().to_Hz());
+
+    let mut i: u8 = 0;
+
+    loop {
+        delay.delay_ms(2_000);
+
+        let mut text: String<20> = String::new();
+        writeln!(&mut text, "loop number: {}\r\n", i).unwrap();
+
+        write_serial(text.as_bytes());
+
+        i += 1;
+        if i >= 10 {
+            hal::rom_data::reset_to_usb_boot(0, 0);
+        }
+    }
+}
+
+/// Writes to the serial port.
+///
+/// We do this with interrupts disabled, to avoid a race hazard with the USB IRQ.
+fn write_serial(byte_array: &[u8]) {
+    let _ = critical_section::with(|_| unsafe {
+        USB_SERIAL.as_mut().map(|serial| serial.write(byte_array))
+    })
+    .unwrap();
+}
+
+/// This function is called whenever the USB Hardware generates
+/// an Interrupt Request
+#[allow(non_snake_case)]
+#[interrupt]
+unsafe fn USBCTRL_IRQ() {
+    let usb_device = USB_DEVICE.as_mut().unwrap();
+    let serial = USB_SERIAL.as_mut().unwrap();
+
+    if usb_device.poll(&mut [serial]) {
+        let mut buf = [0u8; 64];
+
+        match serial.read(&mut buf) {
+            Err(_e) => {}
+            Ok(_count) => {
+                // gets the first 4 bytes of buf
+                if &buf[0..4] == b"stop" {
+                    hal::rom_data::reset_to_usb_boot(0, 0);
+                } else {
+                    let _ = serial.write("write stop to reset to usb boot\r\n".as_bytes());
+                }
+            }
+        }
+    }
+}