add stm32 i2c slave example

embassy-stm32/src/i2c/mod.rs

@@ -70,19 +70,19 @@ pub mod mode {
 #[derive(Debug, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 /// The command kind to the slave from the master
-pub enum CommandKind {
+pub enum SlaveCommandKind {
     /// Write to the slave
-    SlaveReceive,
+    Write,
     /// Read from the slave
-    SlaveSend,
+    Read,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 /// The command kind to the slave from the master and the address that the slave matched
-pub struct Command {
+pub struct SlaveCommand {
     /// The kind of command
-    pub kind: CommandKind,
+    pub kind: SlaveCommandKind,
     /// The address that the slave matched
     pub address: Address,
 }

embassy-stm32/src/i2c/v2.rs

@@ -887,7 +887,7 @@ impl<'d, M: Mode> I2c<'d, M, MultiMaster> {
     /// Listen for incoming I2C messages.
     ///
     /// The listen method is an asynchronous method but it does not require DMA to be asynchronous.
-    pub async fn listen(&mut self) -> Result<Command, Error> {
+    pub async fn listen(&mut self) -> Result<SlaveCommand, Error> {
         let state = self.state;
         self.info.regs.cr1().modify(|reg| {
             reg.set_addrie(true);
@@ -902,12 +902,12 @@ impl<'d, M: Mode> I2c<'d, M, MultiMaster> {
                 // we do not clear the address flag here as it will be cleared by the dma read/write
                 // if we clear it here the clock stretching will stop and the master will read in data before the slave is ready to send it
                 match isr.dir() {
-                    i2c::vals::Dir::WRITE => Poll::Ready(Ok(Command {
-                        kind: CommandKind::SlaveReceive,
+                    i2c::vals::Dir::WRITE => Poll::Ready(Ok(SlaveCommand {
+                        kind: SlaveCommandKind::Write,
                         address: self.determine_matched_address()?,
                     })),
-                    i2c::vals::Dir::READ => Poll::Ready(Ok(Command {
-                        kind: CommandKind::SlaveSend,
+                    i2c::vals::Dir::READ => Poll::Ready(Ok(SlaveCommand {
+                        kind: SlaveCommandKind::Read,
                         address: self.determine_matched_address()?,
                     })),
                 }
@@ -916,30 +916,30 @@ impl<'d, M: Mode> I2c<'d, M, MultiMaster> {
         .await
     }
 
-    /// Respond to a receive command.
-    pub fn blocking_respond_to_receive(&self, read: &mut [u8]) -> Result<(), Error> {
+    /// Respond to a write command.
+    pub fn blocking_respond_to_write(&self, read: &mut [u8]) -> Result<(), Error> {
         let timeout = self.timeout();
         self.slave_read_internal(read, timeout)
     }
 
-    /// Respond to a send command.
-    pub fn blocking_respond_to_send(&mut self, write: &[u8]) -> Result<(), Error> {
+    /// Respond to a read command.
+    pub fn blocking_respond_to_read(&mut self, write: &[u8]) -> Result<(), Error> {
         let timeout = self.timeout();
         self.slave_write_internal(write, timeout)
     }
 }
 
 impl<'d> I2c<'d, Async, MultiMaster> {
-    /// Respond to a receive command.
+    /// Respond to a write command.
     ///
     /// Returns the total number of bytes received.
-    pub async fn respond_to_receive(&mut self, buffer: &mut [u8]) -> Result<usize, Error> {
+    pub async fn respond_to_write(&mut self, buffer: &mut [u8]) -> Result<usize, Error> {
         let timeout = self.timeout();
         timeout.with(self.read_dma_internal_slave(buffer, timeout)).await
     }
 
-    /// Respond to a send request from an I2C master.
-    pub async fn respond_to_send(&mut self, write: &[u8]) -> Result<SendStatus, Error> {
+    /// Respond to a read request from an I2C master.
+    pub async fn respond_to_read(&mut self, write: &[u8]) -> Result<SendStatus, Error> {
         let timeout = self.timeout();
         timeout.with(self.write_dma_internal_slave(write, timeout)).await
     }

examples/stm32g4/src/bin/i2c_slave.rs

@@ -0,0 +1,149 @@
+//! This example shows how to use an stm32 as both a master and a slave.
+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::i2c::{Address, OwnAddresses, SlaveCommandKind};
+use embassy_stm32::mode::Async;
+use embassy_stm32::time::Hertz;
+use embassy_stm32::{bind_interrupts, i2c, peripherals};
+use embassy_time::Timer;
+use {defmt_rtt as _, panic_probe as _};
+
+bind_interrupts!(struct Irqs {
+    I2C1_ER => i2c::ErrorInterruptHandler<peripherals::I2C1>;
+    I2C1_EV => i2c::EventInterruptHandler<peripherals::I2C1>;
+    I2C2_ER => i2c::ErrorInterruptHandler<peripherals::I2C2>;
+    I2C2_EV => i2c::EventInterruptHandler<peripherals::I2C2>;
+});
+
+const DEV_ADDR: u8 = 0x42;
+
+#[embassy_executor::task]
+async fn device_task(mut dev: i2c::I2c<'static, Async, i2c::MultiMaster>) -> ! {
+    info!("Device start");
+
+    let mut state = 0;
+
+    loop {
+        let mut buf = [0u8; 128];
+        match dev.listen().await {
+            Ok(i2c::SlaveCommand {
+                kind: SlaveCommandKind::Read,
+                address: Address::SevenBit(DEV_ADDR),
+            }) => match dev.respond_to_read(&[state]).await {
+                Ok(i2c::SendStatus::LeftoverBytes(x)) => info!("tried to write {} extra bytes", x),
+                Ok(i2c::SendStatus::Done) => {}
+                Err(e) => error!("error while responding {}", e),
+            },
+            Ok(i2c::SlaveCommand {
+                kind: SlaveCommandKind::Write,
+                address: Address::SevenBit(DEV_ADDR),
+            }) => match dev.respond_to_write(&mut buf).await {
+                Ok(len) => {
+                    info!("Device received write: {}", buf[..len]);
+
+                    if match buf[0] {
+                        // Set the state
+                        0xC2 => {
+                            state = buf[1];
+                            true
+                        }
+                        // Reset State
+                        0xC8 => {
+                            state = 0;
+                            true
+                        }
+                        x => {
+                            error!("Invalid Write Read {:x}", x);
+                            false
+                        }
+                    } {
+                        match dev.respond_to_read(&[state]).await {
+                            Ok(read_status) => info!(
+                                "This read is part of a write/read transaction. The response read status {}",
+                                read_status
+                            ),
+                            Err(i2c::Error::Timeout) => {
+                                info!("The device only performed a write and it not also do a read")
+                            }
+                            Err(e) => error!("error while responding {}", e),
+                        }
+                    }
+                }
+                Err(e) => error!("error while receiving {}", e),
+            },
+            Ok(i2c::SlaveCommand { address, .. }) => {
+                defmt::unreachable!(
+                    "The slave matched address: {}, which it was not configured for",
+                    address
+                );
+            }
+            Err(e) => error!("{}", e),
+        }
+    }
+}
+
+#[embassy_executor::task]
+async fn controller_task(mut con: i2c::I2c<'static, Async, i2c::Master>) {
+    info!("Controller start");
+
+    loop {
+        let mut resp_buff = [0u8; 1];
+        for i in 0..10 {
+            match con.write_read(DEV_ADDR, &[0xC2, i], &mut resp_buff).await {
+                Ok(_) => {
+                    info!("write_read response: {}", resp_buff);
+                    defmt::assert_eq!(resp_buff[0], i);
+                }
+                Err(e) => error!("Error writing {}", e),
+            }
+
+            Timer::after_millis(100).await;
+        }
+        match con.read(DEV_ADDR, &mut resp_buff).await {
+            Ok(_) => {
+                info!("read response: {}", resp_buff);
+                // assert that the state is the last index that was written
+                defmt::assert_eq!(resp_buff[0], 9);
+            }
+            Err(e) => error!("Error writing {}", e),
+        }
+        match con.write_read(DEV_ADDR, &[0xC8], &mut resp_buff).await {
+            Ok(_) => {
+                info!("write_read response: {}", resp_buff);
+                // assert that the state has been reset
+                defmt::assert_eq!(resp_buff[0], 0);
+            }
+            Err(e) => error!("Error writing {}", e),
+        }
+        Timer::after_millis(100).await;
+    }
+}
+
+#[embassy_executor::main]
+async fn main(spawner: Spawner) {
+    let p = embassy_stm32::init(Default::default());
+    info!("Hello World!");
+
+    let speed = Hertz::khz(400);
+    let config = i2c::Config::default();
+
+    let d_addr_config = i2c::SlaveAddrConfig {
+        addr: OwnAddresses::OA1(Address::SevenBit(DEV_ADDR)),
+        general_call: false,
+    };
+    let d_sda = p.PA8;
+    let d_scl = p.PA9;
+    let device = i2c::I2c::new(p.I2C2, d_scl, d_sda, Irqs, p.DMA1_CH1, p.DMA1_CH2, speed, config)
+        .into_slave_multimaster(d_addr_config);
+
+    unwrap!(spawner.spawn(device_task(device)));
+
+    let c_sda = p.PB8;
+    let c_scl = p.PB7;
+    let controller = i2c::I2c::new(p.I2C1, c_sda, c_scl, Irqs, p.DMA1_CH3, p.DMA1_CH4, speed, config);
+
+    unwrap!(spawner.spawn(controller_task(controller)));
+}