Starting on RTIC version of loopback-fw.

Currently it operates a USB Serial port.

build.sh

@@ -72,6 +72,10 @@ pushd loopback-fw
 cargo build --target=thumbv7em-none-eabihf --release
 cargo fmt --check
 popd
+pushd loopback-fw-rtic
+cargo build --target=thumbv7em-none-eabihf --release
+cargo fmt --check
+popd
 popd
 
 # Only build the templates (they will panic at run-time due to the use of todo!)
@@ -105,5 +109,6 @@ cp -r ./.cargo "${OUTPUT_NAME}/"
 cp -r ./tools "${OUTPUT_NAME}/"
 cp ./nrf52-code/puzzle-fw/target/thumbv7em-none-eabihf/release/puzzle-fw "${OUTPUT_NAME}/nrf52-code/boards/dongle-fw/puzzle-fw"
 cp ./nrf52-code/loopback-fw/target/thumbv7em-none-eabihf/release/loopback-fw "${OUTPUT_NAME}/nrf52-code/boards/dongle-fw/loopback-fw"
+cp ./nrf52-code/loopback-fw-rtic/target/thumbv7em-none-eabihf/release/loopback-fw-rtic "${OUTPUT_NAME}/nrf52-code/boards/dongle-fw/loopback-fw-rtic"
 find "${OUTPUT_NAME}" -name target -type d -print0 | xargs -0 rm -rf
 zip -r "${OUTPUT_NAME}.zip" "${OUTPUT_NAME}"

nrf52-code/boards/dk/Cargo.toml

@@ -18,3 +18,4 @@ hal = { package = "nrf52840-hal", version = "0.18.0" }
 [features]
 advanced = []
 radio = []
+usbd = []

nrf52-code/boards/dk/src/lib.rs

@@ -17,7 +17,7 @@ use cortex_m_semihosting::debug;
 use embedded_hal::digital::{OutputPin, StatefulOutputPin};
 #[cfg(feature = "advanced")]
 use grounded::uninit::GroundedArrayCell;
-#[cfg(feature = "radio")]
+#[cfg(any(feature = "radio", feature = "usbd"))]
 use grounded::uninit::GroundedCell;
 #[cfg(feature = "radio")]
 pub use hal::ieee802154;
@@ -44,14 +44,18 @@ pub mod peripheral;
 #[cfg(feature = "advanced")]
 pub mod usbd;
 
-#[cfg(feature = "radio")]
+#[cfg(any(feature = "radio", feature = "usbd"))]
 struct ClockSyncWrapper<H, L, LSTAT> {
     clocks: Clocks<H, L, LSTAT>,
 }
 
-#[cfg(feature = "radio")]
+#[cfg(any(feature = "radio", feature = "usbd"))]
 unsafe impl<H, L, LSTAT> Sync for ClockSyncWrapper<H, L, LSTAT> {}
 
+/// Our USB Device
+#[cfg(feature = "usbd")]
+pub type UsbDevice = hal::usbd::Usbd<hal::usbd::UsbPeripheral<'static>>;
+
 /// Components on the board
 pub struct Board {
     /// LEDs
@@ -71,6 +75,9 @@ pub struct Board {
     /// USB control endpoint 0
     #[cfg(feature = "advanced")]
     pub ep0in: Ep0In,
+    /// A configured USB Device
+    #[cfg(feature = "usbd")]
+    pub usbd: UsbDevice,
 }
 
 /// All LEDs on the board
@@ -300,7 +307,7 @@ pub fn init() -> Result<Board, Error> {
     // NOTE: this branch runs at most once
     #[cfg(feature = "advanced")]
     static EP0IN_BUF: GroundedArrayCell<u8, 64> = GroundedArrayCell::const_init();
-    #[cfg(feature = "radio")]
+    #[cfg(any(feature = "radio", feature = "usbd"))]
     // We need the wrapper to make this type Sync, as it contains raw pointers
     static CLOCKS: GroundedCell<
         ClockSyncWrapper<
@@ -317,7 +324,7 @@ pub fn init() -> Result<Board, Error> {
     let clocks = clocks.start_lfclk();
     let _clocks = clocks.enable_ext_hfosc();
     // extend lifetime to `'static`
-    #[cfg(feature = "radio")]
+    #[cfg(any(feature = "radio", feature = "usbd"))]
     let clocks = unsafe {
         let clocks_ptr = CLOCKS.get();
         clocks_ptr.write(ClockSyncWrapper { clocks: _clocks });
@@ -370,6 +377,15 @@ pub fn init() -> Result<Board, Error> {
         radio
     };
 
+    #[cfg(feature = "usbd")]
+    {
+        defmt::debug!("Enabling SOF interrupts...");
+        periph.USBD.inten.modify(|_r, w| {
+            w.sof().set_bit();
+            w
+        });
+    }
+
     Ok(Board {
         leds: Leds {
             _1: Led { inner: led1pin },
@@ -386,6 +402,8 @@ pub fn init() -> Result<Board, Error> {
         power: periph.POWER,
         #[cfg(feature = "advanced")]
         ep0in: unsafe { Ep0In::new(&EP0IN_BUF) },
+        #[cfg(feature = "usbd")]
+        usbd: UsbDevice::new(hal::usbd::UsbPeripheral::new(periph.USBD, clocks)),
     })
 }
 

nrf52-code/loopback-fw-rtic/.cargo/config.toml

@@ -0,0 +1,23 @@
+[target.thumbv7em-none-eabihf]
+# set custom cargo runner to flash & run on embedded target when we call `cargo run`
+# for more information, check out https://github.com/probe-rs
+runner = [
+  "probe-rs",
+  "run",
+  "--chip",
+  "nRF52840_xxAA",
+  "--allow-erase-all",
+  "--log-format",
+  "{t} {[{L}]%bold} {s} {({c:bold} {fff}:{l:1})%dimmed}"
+]
+# Or use "{[{L}]%bold} {s} {({c:bold} {fff}:{l:1})%dimmed}" to disable timestamps
+
+linker = "flip-link" # adds stack overflow protection
+rustflags = [
+  "-C", "link-arg=-Tlink.x", # use the cortex-m-rt linker script
+  "-C", "link-arg=-Tdefmt.x", # defmt support
+]
+
+[build]
+# cross-compile to this target
+target = "thumbv7em-none-eabihf" # = ARM Cortex-M4 with FPU

nrf52-code/loopback-fw-rtic/.gitignore

@@ -0,0 +1 @@
+target