Move pio programs into embassy-rp

1 files changed, 72 insertions, 0 deletions

diff --git a/embassy-rp/src/pio_programs/rotary_encoder.rs b/embassy-rp/src/pio_programs/rotary_encoder.rs
new file mode 100644
index 000000000..323f839bc
--- /dev/null
+++ b/embassy-rp/src/pio_programs/rotary_encoder.rs
@@ -0,0 +1,72 @@
+//! PIO backed quadrature encoder
+
+use crate::gpio::Pull;
+use crate::pio::{self, Common, Config, FifoJoin, Instance, LoadedProgram, PioPin, ShiftDirection, StateMachine};
+use fixed::traits::ToFixed;
+
+/// This struct represents an Encoder program loaded into pio instruction memory.
+pub struct PioEncoderProgram<'a, PIO: Instance> {
+    prg: LoadedProgram<'a, PIO>,
+}
+
+impl<'a, PIO: Instance> PioEncoderProgram<'a, PIO> {
+    /// Load the program into the given pio
+    pub fn new(common: &mut Common<'a, PIO>) -> Self {
+        let prg = pio_proc::pio_asm!("wait 1 pin 1", "wait 0 pin 1", "in pins, 2", "push",);
+
+        let prg = common.load_program(&prg.program);
+
+        Self { prg }
+    }
+}
+
+/// Pio Backed quadrature encoder reader
+pub struct PioEncoder<'d, T: Instance, const SM: usize> {
+    sm: StateMachine<'d, T, SM>,
+}
+
+impl<'d, T: Instance, const SM: usize> PioEncoder<'d, T, SM> {
+    /// Configure a state machine with the loaded [PioEncoderProgram]
+    pub fn new(
+        pio: &mut Common<'d, T>,
+        mut sm: StateMachine<'d, T, SM>,
+        pin_a: impl PioPin,
+        pin_b: impl PioPin,
+        program: &PioEncoderProgram<'d, T>,
+    ) -> Self {
+        let mut pin_a = pio.make_pio_pin(pin_a);
+        let mut pin_b = pio.make_pio_pin(pin_b);
+        pin_a.set_pull(Pull::Up);
+        pin_b.set_pull(Pull::Up);
+        sm.set_pin_dirs(pio::Direction::In, &[&pin_a, &pin_b]);
+
+        let mut cfg = Config::default();
+        cfg.set_in_pins(&[&pin_a, &pin_b]);
+        cfg.fifo_join = FifoJoin::RxOnly;
+        cfg.shift_in.direction = ShiftDirection::Left;
+        cfg.clock_divider = 10_000.to_fixed();
+        cfg.use_program(&program.prg, &[]);
+        sm.set_config(&cfg);
+        sm.set_enable(true);
+        Self { sm }
+    }
+
+    /// Read a single count from the encoder
+    pub async fn read(&mut self) -> Direction {
+        loop {
+            match self.sm.rx().wait_pull().await {
+                0 => return Direction::CounterClockwise,
+                1 => return Direction::Clockwise,
+                _ => {}
+            }
+        }
+    }
+}
+
+/// Encoder Count Direction
+pub enum Direction {
+    /// Encoder turned clockwise
+    Clockwise,
+    /// Encoder turned counter clockwise
+    CounterClockwise,
+}