USB support

Cargo.toml

@@ -13,6 +13,7 @@ members = [
   "examples/rtfm-demo",
   "examples/spi-demo",
   "examples/twi-ssd1306",
+  "examples/usb",
 ]
 
 [profile.dev]
@@ -26,3 +27,6 @@ debug = true
 lto = true
 opt-level = "s"
 
+[patch.crates-io.usb-device]
+git = "https://github.com/jonas-schievink/usb-device.git"
+branch = "inhibit-setaddr-resp"

examples/usb/.cargo/config

@@ -0,0 +1,2 @@
+[target.'cfg(all(target_arch = "arm", target_os = "none"))']
+runner = 'arm-none-eabi-gdb'

examples/usb/.gdbinit

@@ -0,0 +1,13 @@
+# disable "are you sure you want to quit?"
+define hook-quit
+    set confirm off
+end
+
+target remote :3333
+
+# print demangled symbols by default
+set print asm-demangle on
+
+monitor arm semihosting enable
+load
+cont

examples/usb/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "usb"
+version = "0.1.0"
+authors = ["Jonas Schievink <[email protected]>"]
+edition = "2018"
+
+[dependencies]
+cortex-m = "0.6.2"
+cortex-m-rt = "0.6.12"
+cortex-m-semihosting = "0.3.5"
+panic-semihosting = "0.5.3"
+nrf52840-pac = "0.9.0"
+usb-device = "0.2.5"
+usbd-serial = "0.1.0"
+
+[dependencies.nrf52840-hal]
+version = "0.10.0"
+path = "../../nrf52840-hal"

examples/usb/README.md

@@ -0,0 +1,14 @@
+# spi-demo
+SPIM demonstation code.
+Connect a resistor between pin 22 and 23 on the demo board to feed MOSI directly back to MISO
+If all tests pass all four Led (Led1 to Led4) will light up, in case of error only at least one of the Led will remain turned off.
+
+
+## HW connections
+Pin     Connecton
+P0.24   SPIclk
+P0.23   MOSI
+P0.22   MISO
+
+This is designed for nRF52-DK board:
+https://www.nordicsemi.com/Software-and-Tools/Development-Kits/nRF52-DK

examples/usb/src/main.rs

@@ -0,0 +1,84 @@
+#![no_std]
+#![no_main]
+
+use panic_semihosting as _;
+
+use cortex_m::peripheral::SCB;
+use cortex_m_rt::entry;
+use cortex_m_semihosting::hprintln;
+use nrf52840_hal::gpio::{p0, p1, Level};
+use nrf52840_hal::prelude::*;
+use nrf52840_hal::timer::{OneShot, Timer};
+use nrf52840_hal::usbd::Usbd;
+use nrf52840_hal::clocks::Clocks;
+use nrf52840_pac::{interrupt, Peripherals, TIMER0};
+use usb_device::device::{UsbDeviceBuilder, UsbDeviceState, UsbVidPid};
+use usbd_serial::{SerialPort, USB_CLASS_CDC};
+
+#[interrupt]
+fn TIMER0() {
+    SCB::sys_reset();
+}
+
+#[entry]
+fn main() -> ! {
+    static mut EP_BUF: [u8; 512] = [0; 512];
+
+    let periph = Peripherals::take().unwrap();
+    while !periph
+        .POWER
+        .usbregstatus
+        .read()
+        .vbusdetect()
+        .is_vbus_present()
+    {}
+
+    // wait until USB 3.3V supply is stable
+    while !periph
+        .POWER
+        .events_usbpwrrdy
+        .read()
+        .events_usbpwrrdy()
+        .bit_is_clear()
+    {}
+
+    let clocks = Clocks::new(periph.CLOCK);
+    let clocks = clocks.enable_ext_hfosc();
+
+    let mut timer = Timer::one_shot(periph.TIMER0);
+    let usbd = periph.USBD;
+    let p0 = p0::Parts::new(periph.P0);
+    let p1 = p1::Parts::new(periph.P1);
+
+    let mut led = p0.p0_23.into_push_pull_output(Level::High);
+    let btn = p1.p1_00.into_pullup_input();
+    while btn.is_high().unwrap() {}
+
+    timer.enable_interrupt();
+    timer.start(Timer::<TIMER0, OneShot>::TICKS_PER_SECOND * 3);
+
+    led.set_low().unwrap();
+
+    let usb_bus = Usbd::new_alloc(usbd, EP_BUF, &clocks);
+    let mut serial = SerialPort::new(&usb_bus);
+
+    let mut usb_dev = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0x16c0, 0x27dd))
+        .product("nRF52840 Serial Port Demo")
+        .device_class(USB_CLASS_CDC)
+        .max_packet_size_0(64) // (makes control transfers 8x faster)
+        .build();
+
+    hprintln!("<start>").ok();
+    let mut state = UsbDeviceState::Default;
+    loop {
+        if !usb_dev.poll(&mut [&mut serial]) {
+            continue;
+        }
+
+        let new_state = usb_dev.state();
+        if new_state != state {
+            hprintln!("{:?} {:#x}", new_state, usb_dev.bus().device_address()).ok();
+            state = new_state;
+        }
+    }
+}

nrf-hal-common/Cargo.toml

@@ -36,6 +36,10 @@ version = "0.2.3"
 optional = true
 version = "0.9.0"
 
+[dependencies.usb-device]
+version = "0.2.5"
+optional = true
+
 [dependencies.nrf52810-pac]
 optional = true
 version = "0.9.0"
@@ -61,5 +65,5 @@ doc = []
 51 = ["nrf51"]
 52810 = ["nrf52810-pac"]
 52832 = ["nrf52832-pac"]
-52840 = ["nrf52840-pac"]
+52840 = ["nrf52840-pac", "usb-device"]
 9160 = ["nrf9160-pac"]

nrf-hal-common/src/lib.rs

@@ -46,6 +46,8 @@ pub mod uart;
 pub mod uarte;
 #[cfg(not(feature = "9160"))]
 pub mod uicr;
+#[cfg(feature = "52840")]
+pub mod usbd;
 
 pub mod prelude {
     pub use crate::hal::digital::v2::*;

nrf-hal-common/src/usbd/errata.rs

@@ -0,0 +1,57 @@
+/// Writes `val` to `addr`. Used to apply Errata workarounds.
+unsafe fn poke(addr: u32, val: u32) {
+    (addr as *mut u32).write_volatile(val);
+}
+
+/// Reads 32 bits from `addr`.
+unsafe fn peek(addr: u32) -> u32 {
+    (addr as *mut u32).read_volatile()
+}
+
+pub fn pre_enable() {
+    // Works around Erratum 187 on chip revisions 1 and 2.
+    unsafe {
+        poke(0x4006EC00, 0x00009375);
+        poke(0x4006ED14, 0x00000003);
+        poke(0x4006EC00, 0x00009375);
+    }
+
+    pre_wakeup();
+}
+
+pub fn post_enable() {
+    post_wakeup();
+
+    // Works around Erratum 187 on chip revisions 1 and 2.
+    unsafe {
+        poke(0x4006EC00, 0x00009375);
+        poke(0x4006ED14, 0x00000000);
+        poke(0x4006EC00, 0x00009375);
+    }
+}
+
+pub fn pre_wakeup() {
+    // Works around Erratum 171 on chip revisions 1 and 2.
+
+    unsafe {
+        if peek(0x4006EC00) == 0x00000000 {
+            poke(0x4006EC00, 0x00009375);
+        }
+
+        poke(0x4006EC14, 0x000000C0);
+        poke(0x4006EC00, 0x00009375);
+    }
+}
+
+pub fn post_wakeup() {
+    // Works around Erratum 171 on chip revisions 1 and 2.
+
+    unsafe {
+        if peek(0x4006EC00) == 0x00000000 {
+            poke(0x4006EC00, 0x00009375);
+        }
+
+        poke(0x4006EC14, 0x00000000);
+        poke(0x4006EC00, 0x00009375);
+    }
+}