Support for sending UART break conditions (#535)

* Add functions to send over UART with a break

* Fix format

* Update CHANGELOG

* Fixed missing argument

Author: magnusnordlander

CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `Send` for `AsyncCanDriver`
 - `DB_12` ADC attenuation
 - `fade_with_time`, `fade_with_step`, `fade_stop` for `LedcDriver`
+- `write_with_break` for `UartDriver` and `UartTxDriver`
 
 ### Fixed
 - Fix pcnt_rotary_encoder example for esp32

src/uart.rs

@@ -884,6 +884,11 @@ impl<'d> UartDriver<'d> {
         self.tx().write(bytes)
     }
 
+    /// Write multiple bytes from a slice, then send a break condition.
+    pub fn write_with_break(&self, bytes: &[u8], brk_len: i32) -> Result<usize, EspError> {
+        self.tx().write_with_break(bytes, brk_len)
+    }
+
     /// Write multiple bytes from a slice directly to the TX FIFO hardware.
     /// Returns the number of bytes written, where 0 would mean that the TX FIFO is full.
     ///
@@ -1366,6 +1371,20 @@ impl<'d> UartTxDriver<'d> {
         }
     }
 
+    /// Write multiple bytes from a slice, then send a break condition.
+    pub fn write_with_break(&mut self, bytes: &[u8], brk_len: i32) -> Result<usize, EspError> {
+        // `uart_write_bytes_with_break()` returns error (-1) or how many bytes were written
+        let len = unsafe {
+            uart_write_bytes_with_break(self.port(), bytes.as_ptr().cast(), bytes.len(), brk_len)
+        };
+
+        if len >= 0 {
+            Ok(len as usize)
+        } else {
+            Err(EspError::from_infallible::<ESP_ERR_INVALID_STATE>())
+        }
+    }
+
     /// Write multiple bytes from a slice directly to the TX FIFO hardware.
     /// Returns the number of bytes written, where 0 would mean that the TX FIFO is full.
     ///