rp/i2c: add address flexibility and example

Previous i2c examples are using either blocking Embassy API
or e-h traits, this example uses Embassy pub API directly.

Signed-off-by: Krzysztof Królczyk <[email protected]>

1 files changed, 85 insertions, 0 deletions

diff --git a/examples/rp/src/bin/i2c_async_embassy.rs b/examples/rp/src/bin/i2c_async_embassy.rs
new file mode 100644
index 000000000..a65b71b9f
--- /dev/null
+++ b/examples/rp/src/bin/i2c_async_embassy.rs
@@ -0,0 +1,85 @@
+//! This example shows how to communicate asynchronous using i2c with external chip.
+//!
+//! It's using embassy's functions directly instead of traits from embedded_hal_async::i2c::I2c.
+//! While most of i2c devices are addressed using 7 bits, an extension allows 10 bits too.
+
+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_rp::i2c::InterruptHandler;
+use {defmt_rtt as _, panic_probe as _};
+
+// Our anonymous hypotetical temperature sensor could be:
+// a 12-bit sensor, with 100ms startup time, range of -40*C - 125*C, and precision 0.25*C
+// It requires no configuration or calibration, works with all i2c bus speeds,
+// never stretches clock or does anything complicated. Replies with one u16.
+// It requires only one write to take it out of suspend mode, and stays on.
+// Often result would be just on 12 bits, but here we'll simplify it to 16.
+
+enum UncomplicatedSensorId {
+    A(UncomplicatedSensorU8),
+    B(UncomplicatedSensorU16),
+}
+enum UncomplicatedSensorU8 {
+    First = 0x48,
+}
+enum UncomplicatedSensorU16 {
+    Other = 0x0049,
+}
+
+impl Into<u16> for UncomplicatedSensorU16 {
+    fn into(self) -> u16 {
+        self as u16
+    }
+}
+impl Into<u16> for UncomplicatedSensorU8 {
+    fn into(self) -> u16 {
+        0x48
+    }
+}
+impl From<UncomplicatedSensorId> for u16 {
+    fn from(t: UncomplicatedSensorId) -> Self {
+        match t {
+            UncomplicatedSensorId::A(x) => x.into(),
+            UncomplicatedSensorId::B(x) => x.into(),
+        }
+    }
+}
+
+embassy_rp::bind_interrupts!(struct Irqs {
+    I2C1_IRQ => InterruptHandler<embassy_rp::peripherals::I2C1>;
+});
+
+#[embassy_executor::main]
+async fn main(_task_spawner: embassy_executor::Spawner) {
+    let p = embassy_rp::init(Default::default());
+    let sda = p.PIN_14;
+    let scl = p.PIN_15;
+    let config = embassy_rp::i2c::Config::default();
+    let mut bus = embassy_rp::i2c::I2c::new_async(p.I2C1, scl, sda, Irqs, config);
+
+    const WAKEYWAKEY: u16 = 0xBABE;
+    let mut result: [u8; 2] = [0, 0];
+    // wait for sensors to initialize
+    embassy_time::Timer::after(embassy_time::Duration::from_millis(100)).await;
+
+    let _res_1 = bus
+        .write_async(UncomplicatedSensorU8::First, WAKEYWAKEY.to_be_bytes())
+        .await;
+    let _res_2 = bus
+        .write_async(UncomplicatedSensorU16::Other, WAKEYWAKEY.to_be_bytes())
+        .await;
+
+    loop {
+        let s1 = UncomplicatedSensorId::A(UncomplicatedSensorU8::First);
+        let s2 = UncomplicatedSensorId::B(UncomplicatedSensorU16::Other);
+        let sensors = [s1, s2];
+        for sensor in sensors {
+            if bus.read_async(sensor, &mut result).await.is_ok() {
+                info!("Result {}", u16::from_be_bytes(result.into()));
+            }
+        }
+        embassy_time::Timer::after(embassy_time::Duration::from_millis(200)).await;
+    }
+}