Add I2C slave

Author: daniel-nicolai-hansten

CHANGELOG.md

@@ -20,6 +20,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - PWM complementary output capability for TIM1 with new example to demonstrate
 - Implement interface for reading and writing to the internal flash memory and an example for demonstration.
 - PWM output on complementary channels only for single channel timers (TIM16 + TIM17)
+- I2C slave added
 
 ### Fixed
 

Cargo.toml

@@ -98,3 +98,7 @@ required-features = ["stm32f042", "rt"]
 [[example]]
 name = "usb_serial"
 required-features = ["rt", "stm32f042", "stm32-usbd"]
+
+[[example]]
+name = "i2c_slave"
+required-features = ["stm32f030x4", "rt"]

examples/i2c_slave.rs

@@ -0,0 +1,84 @@
+#![no_main]
+#![no_std]
+
+use crate::hal::{
+    gpio::*,
+    pac::{interrupt, Interrupt, Peripherals},
+};
+use cortex_m_rt::entry;
+use panic_halt as _;
+
+// use rtt_target::{rprintln, rtt_init_print};
+use stm32f0xx_hal::i2c_slave::{self, I2CSlave, State};
+use stm32f0xx_hal::{self as hal, prelude::*};
+
+use core::cell::RefCell;
+use cortex_m::{interrupt::Mutex, peripheral::Peripherals as c_m_Peripherals};
+type SCL = gpioa::PA9<Alternate<AF4>>;
+type SDA = gpioa::PA10<Alternate<AF4>>;
+type I2C = hal::pac::I2C1;
+// Make I2C pin globally available
+static GI2C: Mutex<RefCell<Option<I2CSlave<I2C, SCL, SDA>>>> = Mutex::new(RefCell::new(None));
+
+#[interrupt]
+fn I2C1() {
+    static mut I2C: Option<I2CSlave<I2C, SCL, SDA>> = None;
+
+    let i2c = I2C.get_or_insert_with(|| {
+        cortex_m::interrupt::free(|cs| {
+            // Move I2C pin here, leaving a None in its place
+            GI2C.borrow(cs).replace(None).unwrap()
+        })
+    });
+    match i2c.interrupt() {
+        Ok(State::Buzy(_flag)) => {
+            // rprintln!("I2C is busy {:?}", _flag);
+        }
+        Ok(State::DataReceived(_reg)) => {
+            let _data = i2c.get_received_data();
+            // rprintln!("Reg: {:?} Data: {:?}", _reg, _data);
+        }
+        Ok(State::DataRequested(_reg)) => {
+            // rprintln!("Data requested: {:?}", _reg);
+            if let Err(_e) = i2c.send_data(&[0x01, 0x02, 0x03]) {
+                // rprintln!("Error {:?}", _e);
+            }
+        }
+        Err(_e) => {
+            // rprintln!("Error {:?}", e);
+        }
+    }
+}
+
+static I2C_ADDR: u8 = 0x52;
+#[entry]
+fn main() -> ! {
+    // rtt_init_print!();
+    // rprintln!("Starting I2C Slave example...");
+    if let (Some(mut p), Some(cp)) = (Peripherals::take(), c_m_Peripherals::take()) {
+        cortex_m::interrupt::free(move |cs| {
+            p.RCC.apb1enr.modify(|_, w| w.i2c1en().set_bit());
+            let mut rcc = p.RCC.configure().sysclk(48.mhz()).pclk(24.mhz()).freeze(&mut p.FLASH);
+            let gpioa = p.GPIOA.split(&mut rcc);
+
+            // Configure pins for I2C
+            let sda = gpioa.pa10.into_alternate_af4(cs);
+            let scl = gpioa.pa9.into_alternate_af4(cs);
+            let i2c = i2c_slave::I2CSlave::i2c1_slave(p.I2C1, (scl, sda), I2C_ADDR, &mut rcc);
+            *GI2C.borrow(cs).borrow_mut() = Some(i2c);
+
+            // Enable I2C IRQ, set prio 1 and clear any pending IRQs
+            let mut nvic = cp.NVIC;
+            unsafe {
+                nvic.set_priority(Interrupt::I2C1, 1);
+                cortex_m::peripheral::NVIC::unmask(Interrupt::I2C1);
+            }
+
+            cortex_m::peripheral::NVIC::unpend(Interrupt::I2C1);
+        });
+    }
+
+    loop {
+        continue;
+    }
+}