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 <Krzysztof.Krolczyk@o2.pl>

embassy-rp/src/i2c.rs

@@ -313,25 +313,29 @@ impl<'d, T: Instance> I2c<'d, T, Async> {
     }
 
     /// Read from address into buffer using DMA.
-    pub async fn read_async(&mut self, addr: u16, buffer: &mut [u8]) -> Result<(), Error> {
+    pub async fn read_async(&mut self, addr: impl Into<u16>, buffer: &mut [u8]) -> Result<(), Error> {
-        Self::setup(addr)?;
+        Self::setup(addr.into())?;
         self.read_async_internal(buffer, true, true).await
     }
 
     /// Write to address from buffer using DMA.
-    pub async fn write_async(&mut self, addr: u16, bytes: impl IntoIterator<Item = u8>) -> Result<(), Error> {
+    pub async fn write_async(
-        Self::setup(addr)?;
+        &mut self,
+        addr: impl Into<u16>,
+        bytes: impl IntoIterator<Item = u8>,
+    ) -> Result<(), Error> {
+        Self::setup(addr.into())?;
         self.write_async_internal(bytes, true).await
     }
 
     /// Write to address from bytes and read from address into buffer using DMA.
     pub async fn write_read_async(
         &mut self,
-        addr: u16,
+        addr: impl Into<u16>,
         bytes: impl IntoIterator<Item = u8>,
         buffer: &mut [u8],
     ) -> Result<(), Error> {
-        Self::setup(addr)?;
+        Self::setup(addr.into())?;
         self.write_async_internal(bytes, false).await?;
         self.read_async_internal(buffer, true, true).await
     }
@@ -595,20 +599,20 @@ impl<'d, T: Instance + 'd, M: Mode> I2c<'d, T, M> {
     // =========================
 
     /// Read from address into buffer blocking caller until done.
-    pub fn blocking_read(&mut self, address: u8, read: &mut [u8]) -> Result<(), Error> {
+    pub fn blocking_read(&mut self, address: impl Into<u16>, read: &mut [u8]) -> Result<(), Error> {
         Self::setup(address.into())?;
         self.read_blocking_internal(read, true, true)
         // Automatic Stop
     }
 
     /// Write to address from buffer blocking caller until done.
-    pub fn blocking_write(&mut self, address: u8, write: &[u8]) -> Result<(), Error> {
+    pub fn blocking_write(&mut self, address: impl Into<u16>, write: &[u8]) -> Result<(), Error> {
         Self::setup(address.into())?;
         self.write_blocking_internal(write, true)
     }
 
     /// Write to address from bytes and read from address into buffer blocking caller until done.
-    pub fn blocking_write_read(&mut self, address: u8, write: &[u8], read: &mut [u8]) -> Result<(), Error> {
+    pub fn blocking_write_read(&mut self, address: impl Into<u16>, write: &[u8], read: &mut [u8]) -> Result<(), Error> {
         Self::setup(address.into())?;
         self.write_blocking_internal(write, false)?;
         self.read_blocking_internal(read, true, true)
@@ -719,25 +723,15 @@ where
     T: Instance + 'd,
 {
     async fn read(&mut self, address: A, read: &mut [u8]) -> Result<(), Self::Error> {
-        let addr: u16 = address.into();
+        self.read_async(address, read).await
-
-        Self::setup(addr)?;
-        self.read_async_internal(read, false, true).await
     }
 
     async fn write(&mut self, address: A, write: &[u8]) -> Result<(), Self::Error> {
-        let addr: u16 = address.into();
+        self.write_async(address, write.iter().copied()).await
-
-        Self::setup(addr)?;
-        self.write_async_internal(write.iter().copied(), true).await
     }
 
     async fn write_read(&mut self, address: A, write: &[u8], read: &mut [u8]) -> Result<(), Self::Error> {
-        let addr: u16 = address.into();
+        self.write_read_async(address, write.iter().copied(), read).await
-
-        Self::setup(addr)?;
-        self.write_async_internal(write.iter().cloned(), false).await?;
-        self.read_async_internal(read, true, true).await
     }
 
     async fn transaction(

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;
+    }
+}