Make it possible to construct DynPin from scratch

rp2040-hal/examples/gpio_c_interop.rs

@@ -0,0 +1,103 @@
+#![no_std]
+#![no_main]
+
+// Ensure we halt the program on panic (if we don't mention this crate it won't
+// be linked)
+use panic_halt as _;
+
+// Alias for our HAL crate
+use rp2040_hal as hal;
+
+// A shorter alias for the Peripheral Access Crate, which provides low-level
+// register access
+use hal::pac;
+
+// Some traits we need
+use embedded_hal::digital::v2::ToggleableOutputPin;
+
+use hal::gpio::*;
+use hal::gpio::DynGroup::Bank0;
+use hal::gpio::DynOutput::PushPull;
+use hal::Clock;
+// use crate::DynRegisters;
+
+/// The linker will place this boot block at the start of our program image. We
+/// need this to help the ROM bootloader get our code up and running.
+/// Note: This boot block is not necessary when using a rp-hal based BSP
+/// as the BSPs already perform this step.
+#[link_section = ".boot2"]
+#[used]
+pub static BOOT2: [u8; 256] = rp2040_boot2::BOOT_LOADER_GENERIC_03H;
+
+/// External high-speed crystal on the Raspberry Pi Pico board is 12 MHz. Adjust
+/// if your board has a different frequency
+const XTAL_FREQ_HZ: u32 = 12_000_000u32;
+
+/// This function will construct a DynPin (based on pin_id) and use it to toggle the GPIO
+/// It assumes that the pin is already in the correct mode
+extern "C" fn do_work(pin_id: u8) {
+    let pin = DynPinId {
+        group: Bank0,
+        num: pin_id,
+    };
+    let mode = DynPinMode::Output(PushPull);
+    let mut dynpin1 = unsafe { DynPin::new(pin, mode) };
+    // Panic if the pin wasn't in the right mode
+    dynpin1.toggle().unwrap();
+}
+
+/// Entry point to our bare-metal application.
+///
+/// The `#[rp2040_hal::entry]` macro ensures the Cortex-M start-up code calls this function
+/// as soon as all global variables and the spinlock are initialised.
+///
+/// The function configures the RP2040 peripherals, then toggles a GPIO pin in
+/// an infinite loop. If there is an LED connected to that pin, it will blink.
+#[rp2040_hal::entry]
+fn main() -> ! {
+    // Grab our singleton objects
+    let mut pac = pac::Peripherals::take().unwrap();
+    let core = pac::CorePeripherals::take().unwrap();
+
+
+    // Set up the watchdog driver - needed by the clock setup code
+    let mut watchdog = hal::Watchdog::new(pac.WATCHDOG);
+
+    // Configure the clocks
+    let clocks = hal::clocks::init_clocks_and_plls(
+        XTAL_FREQ_HZ,
+        pac.XOSC,
+        pac.CLOCKS,
+        pac.PLL_SYS,
+        pac.PLL_USB,
+        &mut pac.RESETS,
+        &mut watchdog,
+    )
+    .ok()
+    .unwrap();
+
+    let mut delay = cortex_m::delay::Delay::new(core.SYST, clocks.system_clock.freq().to_Hz());
+
+    // The single-cycle I/O block controls our GPIO pins
+    let sio = hal::Sio::new(pac.SIO);
+
+    // Set the pins to their default state
+    let pins = hal::gpio::Pins::new(
+        pac.IO_BANK0,
+        pac.PADS_BANK0,
+        sio.gpio_bank0,
+        &mut pac.RESETS,
+    );
+
+    // The pin number to use as an output
+    let pin_number:u8 = 25;
+    // We'll put the pin in the correct mode first, though C code might do this too
+    pins.gpio25.into_push_pull_output();
+
+    loop {
+        do_work(pin_number);
+        delay.delay_ms(500);
+    }
+}
+
+// End of file

rp2040-hal/src/gpio/dynpin.rs

@@ -305,7 +305,7 @@ impl DynPin {
     /// must be at most one corresponding [`DynPin`] in existence at any given
     /// time.  Violating this requirement is `unsafe`.
     #[inline]
-    unsafe fn new(id: DynPinId, mode: DynPinMode) -> Self {
+    pub unsafe fn new(id: DynPinId, mode: DynPinMode) -> Self {
         DynPin {
             regs: DynRegisters::new(id),
             mode,