Feature/i2c nonblocking (#98)

* Implemented non-blocking i2c, with watchdog and slave address change possebility

* Added features to cargo.toml i2c-blocking and i2c-nonblocking

* Added default feature i2c-blocking to solve compilation problem

* Added address and direction to result, to be able to fully parse the result in RTIC.

* Formatting cargo fmt

* Simplified frame handling, to make use more easy. See comments on traits

* Fixed small bug

Author: smeenka

Cargo.toml

@@ -49,6 +49,7 @@ st7735-lcd = "0.6.1"
 ws2812-spi = { version = "0.3.0", features = [] }
 
 [features]
+default = ["i2c-blocking"]
 device-selected = []
 rt = ["stm32g0/rt"]
 stm32g030 = ["stm32g0/stm32g030", "stm32g0x0", "device-selected"]
@@ -61,6 +62,9 @@ stm32g081 = ["stm32g0/stm32g081", "stm32g0x1", "device-selected"]
 stm32g0x0 = []
 stm32g0x1 = []
 
+i2c-blocking = []
+i2c-nonblocking = []
+
 [profile.dev]
 incremental = false
 

src/i2c/mod.rs

@@ -1,4 +1,12 @@
+#[cfg(feature = "i2c-blocking")]
 pub mod blocking;
+
+#[cfg(feature = "i2c-nonblocking")]
+pub mod nonblocking;
+
+#[cfg(feature = "i2c-nonblocking")]
+pub use nonblocking::*;
+
 pub mod config;
 
 use crate::rcc::*;
@@ -16,6 +24,12 @@ pub enum SlaveAddressMask {
     MaskAllBits,
 }
 
+#[derive(Debug, Clone, Copy)]
+pub enum I2cResult<'a> {
+    Data(u16, I2cDirection, &'a [u8]), // contains address, direction and data slice reference
+    Addressed(u16, I2cDirection),      // a slave is addressed by a master
+}
+
 #[derive(Debug, Clone, Copy)]
 pub enum I2cDirection {
     MasterReadSlaveWrite = 0,
@@ -59,8 +73,24 @@ pub trait I2cExt<I2C> {
 }
 
 /// I2C abstraction
+#[cfg(feature = "i2c-blocking")]
+pub struct I2c<I2C, SDA, SCL> {
+    i2c: I2C,
+    sda: SDA,
+    scl: SCL,
+}
+
+#[cfg(feature = "i2c-nonblocking")]
 pub struct I2c<I2C, SDA, SCL> {
     i2c: I2C,
     sda: SDA,
     scl: SCL,
+    address: u16,
+    watchdog: u16, // on each start set to 10, on each stop set to 0
+    index: usize,
+    length: usize,
+    errors: usize,            // global error counter, reset on read
+    length_write_read: usize, // for a master write_read operation this remembers the size of the read operation
+    // for a slave device this must be 0
+    data: [u8; 255], // during transfer the driver will be the owner of the buffer
 }