example of side setting using PIO

rp2040-hal/examples/pio_side_set.rs

@@ -0,0 +1,65 @@
+//! This example toggles the GPIO25 pin, using a PIO program compiled via pio_proc::pio!().
+//!
+//! If a LED is connected to that pin, like on a Pico board, the LED should blink.
+//!
+//! This example makes use of side setting.
+#![no_std]
+#![no_main]
+
+use cortex_m_rt::entry;
+use hal::gpio::{FunctionPio0, Pin};
+use hal::pac;
+use hal::pio::PIOExt;
+use hal::Sio;
+use panic_halt as _;
+use rp2040_hal as hal;
+
+#[link_section = ".boot2"]
+#[used]
+pub static BOOT2: [u8; 256] = rp2040_boot2::BOOT_LOADER_W25Q080;
+
+#[entry]
+fn main() -> ! {
+    let mut pac = pac::Peripherals::take().unwrap();
+
+    let sio = Sio::new(pac.SIO);
+    let pins = hal::gpio::Pins::new(
+        pac.IO_BANK0,
+        pac.PADS_BANK0,
+        sio.gpio_bank0,
+        &mut pac.RESETS,
+    );
+
+    // configure LED pin for Pio0.
+    let _led: Pin<_, FunctionPio0> = pins.gpio25.into_mode();
+    // PIN id for use inside of PIO
+    let led_pin_id = 25;
+
+    // Define some simple PIO program.
+    let program = pio_proc::pio!(
+        32,
+        "
+        .side_set 1 ; each instruction may set 1 bit
+        .wrap_target
+            nop side 1
+            nop side 0
+        .wrap
+        "
+    );
+
+    // Initialize and start PIO
+    let (mut pio, sm0, _, _, _) = pac.PIO0.split(&mut pac.RESETS);
+    let installed = pio.install(&program.program).unwrap();
+    let div = 0f32; // as slow as possible (0 is interpreted as 65536)
+    let (mut sm, _, _) = rp2040_hal::pio::PIOBuilder::from_program(installed)
+        .side_set_pin_base(led_pin_id)
+        .clock_divisor(div)
+        .build(sm0);
+    // The GPIO pin needs to be configured as an output.
+    sm.set_pindirs([(led_pin_id, hal::pio::PinDir::Output)]);
+    sm.start();
+
+    // PIO runs in background, independently from CPU
+    #[allow(clippy::empty_loop)]
+    loop {}
+}