Fix Async UART (#871)

* Fix Async UART

The uart handler was `writing` to the enable register instead of
`modify`, which meant any wake would see the cleared enabled bit and
think the event had occurred. This wasn't seen before the split of uart
because it was only possible to listen to one thing at a time.

This PR also removes the ReadBufferFull error in favour of returning the
max bytes in the buffer.

The serial examples has been updated to actually have some cross task
communication.

* changelog

* fix dev deps

.vscode/settings.json

@@ -23,6 +23,12 @@
   ],
 
   "[toml]": {
-    "editor.formatOnSave": false
+    "editor.formatOnSave": false,
+  },
+  "[markdown]": {
+    "editor.formatOnSave": false,
+  },
+  "[jsonc]": {
+    "editor.formatOnSave": false,
   }
 }

CHANGELOG.md

@@ -45,6 +45,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Xtensa targets: Use ESP32Reset - not Reset (#823)
 - Examples should now work with the `defmt` feature (#810)
 - Fixed a race condition causing SpiDma to stop working unexpectedly (#869)
+- Fixed async uart serial, and updated the embassy_serial examples (#871).
 
 ### Removed
 

esp-hal-common/src/uart.rs

@@ -61,8 +61,6 @@ const UART_FIFO_SIZE: u16 = 128;
 pub enum Error {
     InvalidArgument,
     #[cfg(feature = "async")]
-    ReadBufferFull,
-    #[cfg(feature = "async")]
     RxFifoOvf,
 }
 
@@ -854,6 +852,8 @@ pub trait Instance {
                 .set_bit()
                 .rxfifo_tout_int_clr()
                 .set_bit()
+                .at_cmd_char_det_int_clr()
+                .set_bit()
         });
 
         Self::register_block().int_ena.write(|w| {
@@ -863,6 +863,8 @@ pub trait Instance {
                 .clear_bit()
                 .rxfifo_tout_int_ena()
                 .clear_bit()
+                .at_cmd_char_det_int_ena()
+                .clear_bit()
         });
     }
 
@@ -1374,8 +1376,6 @@ mod asynch {
         /// - `buf` buffer slice to write the bytes into
         ///
         /// # Errors
-        /// - `Err(ReadBufferFull)` if provided buffer slice is not enough to
-        ///   copy all avaialble bytes. Increase buffer slice length.
         /// - `Err(RxFifoOvf)` when MCU Rx Fifo Overflow interrupt is triggered.
         ///   To avoid this error, call this function more often.
         /// - `Err(Error::ReadNoConfig)` if neither `set_rx_fifo_full_threshold`
@@ -1448,8 +1448,6 @@ mod asynch {
         /// - `buf` buffer slice to write the bytes into
         ///
         /// # Errors
-        /// - `Err(ReadBufferFull)` if provided buffer slice is not enough to
-        ///   copy all avaialble bytes. Increase buffer slice length.
         /// - `Err(RxFifoOvf)` when MCU Rx Fifo Overflow interrupt is triggered.
         ///   To avoid this error, call this function more often.
         /// - `Err(Error::ReadNoConfig)` if neither `set_rx_fifo_full_threshold`
@@ -1459,6 +1457,10 @@ mod asynch {
         /// When succesfull, returns the number of bytes written to
         /// buf
         async fn read_async(&mut self, buf: &mut [u8]) -> Result<usize, Error> {
+            if buf.len() == 0 {
+                return Ok(0);
+            }
+
             let mut read_bytes = 0;
 
             if self.at_cmd_config.is_some() {
@@ -1487,7 +1489,7 @@ mod asynch {
                     buf[read_bytes] = byte;
                     read_bytes += 1;
                 } else {
-                    return Err(Error::ReadBufferFull);
+                    break;
                 }
             }
 
@@ -1540,20 +1542,25 @@ mod asynch {
     }
 
     fn intr_handler(uart: &RegisterBlock) -> bool {
-        let int_ena_val = uart.int_ena.read();
         let int_raw_val = uart.int_raw.read();
+        let int_ena_val = uart.int_ena.read();
+
+        let mut wake = false;
 
         if int_ena_val.txfifo_empty_int_ena().bit_is_set()
             && int_raw_val.txfifo_empty_int_raw().bit_is_set()
         {
-            uart.int_ena.write(|w| w.txfifo_empty_int_ena().clear_bit());
+            uart.int_clr.write(|w| w.txfifo_empty_int_clr().set_bit());
-            return true;
+            uart.int_ena
+                .modify(|_, w| w.txfifo_empty_int_ena().clear_bit());
+            wake = true;
         }
 
         if int_ena_val.tx_done_int_ena().bit_is_set() && int_raw_val.tx_done_int_raw().bit_is_set()
         {
-            uart.int_ena.write(|w| w.tx_done_int_ena().clear_bit());
+            uart.int_clr.write(|w| w.tx_done_int_clr().set_bit());
-            return true;
+            uart.int_ena.modify(|_, w| w.tx_done_int_ena().clear_bit());
+            wake = true;
         }
 
         if int_ena_val.at_cmd_char_det_int_ena().bit_is_set()
@@ -1562,27 +1569,29 @@ mod asynch {
             uart.int_clr
                 .write(|w| w.at_cmd_char_det_int_clr().set_bit());
             uart.int_ena
-                .write(|w| w.at_cmd_char_det_int_ena().clear_bit());
+                .modify(|_, w| w.at_cmd_char_det_int_ena().clear_bit());
-            return true;
+            wake = true;
         }
 
         if int_ena_val.rxfifo_full_int_ena().bit_is_set()
             && int_raw_val.rxfifo_full_int_raw().bit_is_set()
         {
             uart.int_clr.write(|w| w.rxfifo_full_int_clr().set_bit());
-            uart.int_ena.write(|w| w.rxfifo_full_int_ena().clear_bit());
+            uart.int_ena
-            return true;
+                .modify(|_, w| w.rxfifo_full_int_ena().clear_bit());
+            wake = true;
         }
 
         if int_ena_val.rxfifo_ovf_int_ena().bit_is_set()
             && int_raw_val.rxfifo_ovf_int_raw().bit_is_set()
         {
             uart.int_clr.write(|w| w.rxfifo_ovf_int_clr().set_bit());
-            uart.int_ena.write(|w| w.rxfifo_ovf_int_ena().clear_bit());
+            uart.int_ena
-            return true;
+                .modify(|_, w| w.rxfifo_ovf_int_ena().clear_bit());
+            wake = true;
         }
 
-        false
+        wake
     }
 
     #[cfg(uart0)]

esp32-hal/examples/embassy_serial.rs

@@ -8,18 +8,18 @@
 #![feature(type_alias_impl_trait)]
 
 use embassy_executor::Spawner;
+use embassy_sync::{blocking_mutex::raw::NoopRawMutex, signal::Signal};
 use esp32_hal::{
     clock::ClockControl,
-    embassy::{self},
+    embassy,
     interrupt,
     peripherals::{Interrupt, Peripherals, UART0},
     prelude::*,
-    timer::TimerGroup,
     Uart,
 };
 use esp_backtrace as _;
 use esp_hal_common::uart::{config::AtCmdConfig, UartRx, UartTx};
-use heapless::Vec;
+use static_cell::make_static;
 
 // rx_fifo_full_threshold
 const READ_BUF_SIZE: usize = 64;
@@ -27,8 +27,8 @@ const READ_BUF_SIZE: usize = 64;
 const AT_CMD: u8 = 0x04;
 
 #[embassy_executor::task]
-async fn writer(mut tx: UartTx<'static, UART0>) {
+async fn writer(mut tx: UartTx<'static, UART0>, signal: &'static Signal<NoopRawMutex, usize>) {
-    esp_println::println!("writing...");
+    use core::fmt::Write;
     embedded_io_async::Write::write(
         &mut tx,
         b"Hello async serial. Enter something ended with EOT (CTRL-D).\r\n",
@@ -36,27 +36,30 @@ async fn writer(mut tx: UartTx<'static, UART0>) {
     .await
     .unwrap();
     embedded_io_async::Write::flush(&mut tx).await.unwrap();
+    loop {
+        let bytes_read = signal.wait().await;
+        signal.reset();
+        write!(&mut tx, "\r\n-- received {} bytes --\r\n", bytes_read).unwrap();
+        embedded_io_async::Write::flush(&mut tx).await.unwrap();
+    }
 }
 
 #[embassy_executor::task]
-async fn reader(mut rx: UartRx<'static, UART0>) {
+async fn reader(mut rx: UartRx<'static, UART0>, signal: &'static Signal<NoopRawMutex, usize>) {
-    esp_println::println!("reading...");
-    // max message size to receive
-    // leave some extra space for AT-CMD characters
     const MAX_BUFFER_SIZE: usize = 10 * READ_BUF_SIZE + 16;
 
-    let mut rbuf: Vec<u8, MAX_BUFFER_SIZE> = Vec::new();
+    let mut rbuf: [u8; MAX_BUFFER_SIZE] = [0u8; MAX_BUFFER_SIZE];
     let mut offset = 0;
-    while let Ok(len) = embedded_io_async::Read::read(&mut rx, &mut rbuf[offset..]).await {
+    loop {
-        offset += len;
+        let r = embedded_io_async::Read::read(&mut rx, &mut rbuf[offset..]).await;
-        if offset == 0 {
+        match r {
-            rbuf.truncate(0);
+            Ok(len) => {
-            break;
+                offset += len;
-        }
+                esp_println::println!("Read: {len}, data: {:?}", &rbuf[..offset]);
-        // if set_at_cmd is used than stop reading
+                offset = 0;
-        if len < READ_BUF_SIZE {
+                signal.signal(len);
-            rbuf.truncate(offset);
+            }
-            break;
+            Err(e) => esp_println::println!("RX Error: {:?}", e),
         }
     }
 }
@@ -68,8 +71,17 @@ async fn main(spawner: Spawner) {
     let system = peripherals.SYSTEM.split();
     let clocks = ClockControl::boot_defaults(system.clock_control).freeze();
 
-    let timer_group0 = TimerGroup::new(peripherals.TIMG0, &clocks);
+    #[cfg(feature = "embassy-time-systick")]
-    embassy::init(&clocks, timer_group0.timer0);
+    embassy::init(
+        &clocks,
+        esp32_hal::systimer::SystemTimer::new(peripherals.SYSTIMER),
+    );
+
+    #[cfg(feature = "embassy-time-timg0")]
+    {
+        let timer_group0 = esp32_hal::timer::TimerGroup::new(peripherals.TIMG0, &clocks);
+        embassy::init(&clocks, timer_group0.timer0);
+    }
 
     let mut uart0 = Uart::new(peripherals.UART0, &clocks);
     uart0.set_at_cmd(AtCmdConfig::new(None, None, None, AT_CMD, None));
@@ -80,6 +92,8 @@ async fn main(spawner: Spawner) {
 
     interrupt::enable(Interrupt::UART0, interrupt::Priority::Priority1).unwrap();
 
-    spawner.spawn(reader(rx)).ok();
+    let signal = &*make_static!(Signal::new());
-    spawner.spawn(writer(tx)).ok();
+
+    spawner.spawn(reader(rx, &signal)).ok();
+    spawner.spawn(writer(tx, &signal)).ok();
 }

esp32c2-hal/Cargo.toml

@@ -47,6 +47,7 @@ crypto-bigint     = {version = "0.5.1", default-features = false }
 elliptic-curve    = {version = "0.13.4", default-features = false, features = ["sec1"] }
 p192              = {version = "0.13.0", default-features = false, features = ["arithmetic"] }
 p256              = {version = "0.13.2", default-features = false, features = ["arithmetic"] }
+embassy-sync       = "0.2.0"
 
 [features]
 default              = ["rt", "vectored", "xtal-40mhz"]

esp32c2-hal/examples/embassy_serial.rs

@@ -8,6 +8,7 @@
 #![feature(type_alias_impl_trait)]
 
 use embassy_executor::Spawner;
+use embassy_sync::{blocking_mutex::raw::NoopRawMutex, signal::Signal};
 use esp32c2_hal::{
     clock::ClockControl,
     embassy,
@@ -18,7 +19,7 @@ use esp32c2_hal::{
 };
 use esp_backtrace as _;
 use esp_hal_common::uart::{config::AtCmdConfig, UartRx, UartTx};
-use heapless::Vec;
+use static_cell::make_static;
 
 // rx_fifo_full_threshold
 const READ_BUF_SIZE: usize = 64;
@@ -26,8 +27,8 @@ const READ_BUF_SIZE: usize = 64;
 const AT_CMD: u8 = 0x04;
 
 #[embassy_executor::task]
-async fn writer(mut tx: UartTx<'static, UART0>) {
+async fn writer(mut tx: UartTx<'static, UART0>, signal: &'static Signal<NoopRawMutex, usize>) {
-    esp_println::println!("writing...");
+    use core::fmt::Write;
     embedded_io_async::Write::write(
         &mut tx,
         b"Hello async serial. Enter something ended with EOT (CTRL-D).\r\n",
@@ -35,27 +36,30 @@ async fn writer(mut tx: UartTx<'static, UART0>) {
     .await
     .unwrap();
     embedded_io_async::Write::flush(&mut tx).await.unwrap();
+    loop {
+        let bytes_read = signal.wait().await;
+        signal.reset();
+        write!(&mut tx, "\r\n-- received {} bytes --\r\n", bytes_read).unwrap();
+        embedded_io_async::Write::flush(&mut tx).await.unwrap();
+    }
 }
 
 #[embassy_executor::task]
-async fn reader(mut rx: UartRx<'static, UART0>) {
+async fn reader(mut rx: UartRx<'static, UART0>, signal: &'static Signal<NoopRawMutex, usize>) {
-    esp_println::println!("reading...");
-    // max message size to receive
-    // leave some extra space for AT-CMD characters
     const MAX_BUFFER_SIZE: usize = 10 * READ_BUF_SIZE + 16;
 
-    let mut rbuf: Vec<u8, MAX_BUFFER_SIZE> = Vec::new();
+    let mut rbuf: [u8; MAX_BUFFER_SIZE] = [0u8; MAX_BUFFER_SIZE];
     let mut offset = 0;
-    while let Ok(len) = embedded_io_async::Read::read(&mut rx, &mut rbuf[offset..]).await {
+    loop {
-        offset += len;
+        let r = embedded_io_async::Read::read(&mut rx, &mut rbuf[offset..]).await;
-        if offset == 0 {
+        match r {
-            rbuf.truncate(0);
+            Ok(len) => {
-            break;
+                offset += len;
-        }
+                esp_println::println!("Read: {len}, data: {:?}", &rbuf[..offset]);
-        // if set_at_cmd is used than stop reading
+                offset = 0;
-        if len < READ_BUF_SIZE {
+                signal.signal(len);
-            rbuf.truncate(offset);
+            }
-            break;
+            Err(e) => esp_println::println!("RX Error: {:?}", e),
         }
     }
 }
@@ -74,10 +78,10 @@ async fn main(spawner: Spawner) {
     );
 
     #[cfg(feature = "embassy-time-timg0")]
-    embassy::init(
+    {
-        &clocks,
+        let timer_group0 = esp32c2_hal::timer::TimerGroup::new(peripherals.TIMG0, &clocks);
-        esp32c2_hal::timer::TimerGroup::new(peripherals.TIMG0, &clocks).timer0,
+        embassy::init(&clocks, timer_group0.timer0);
-    );
+    }
 
     let mut uart0 = Uart::new(peripherals.UART0, &clocks);
     uart0.set_at_cmd(AtCmdConfig::new(None, None, None, AT_CMD, None));
@@ -88,6 +92,8 @@ async fn main(spawner: Spawner) {
 
     interrupt::enable(Interrupt::UART0, interrupt::Priority::Priority1).unwrap();
 
-    spawner.spawn(reader(rx)).ok();
+    let signal = &*make_static!(Signal::new());
-    spawner.spawn(writer(tx)).ok();
+
+    spawner.spawn(reader(rx, &signal)).ok();
+    spawner.spawn(writer(tx, &signal)).ok();
 }

esp32c3-hal/Cargo.toml

@@ -50,6 +50,7 @@ sha2               = { version = "0.10.7", default-features = false }
 smart-leds         = "0.3.0"
 ssd1306            = "0.8.1"
 static_cell        = { version = "1.2.0", features = ["nightly"] }
+embassy-sync       = "0.2.0"
 
 [features]
 default              = ["rt", "vectored", "esp-hal-common/rv-zero-rtc-bss"]

esp32c3-hal/examples/embassy_serial.rs

@@ -8,6 +8,7 @@
 #![feature(type_alias_impl_trait)]
 
 use embassy_executor::Spawner;
+use embassy_sync::{blocking_mutex::raw::NoopRawMutex, signal::Signal};
 use esp32c3_hal::{
     clock::ClockControl,
     embassy,
@@ -18,7 +19,7 @@ use esp32c3_hal::{
 };
 use esp_backtrace as _;
 use esp_hal_common::uart::{config::AtCmdConfig, UartRx, UartTx};
-use heapless::Vec;
+use static_cell::make_static;
 
 // rx_fifo_full_threshold
 const READ_BUF_SIZE: usize = 64;
@@ -26,8 +27,8 @@ const READ_BUF_SIZE: usize = 64;
 const AT_CMD: u8 = 0x04;
 
 #[embassy_executor::task]
-async fn writer(mut tx: UartTx<'static, UART0>) {
+async fn writer(mut tx: UartTx<'static, UART0>, signal: &'static Signal<NoopRawMutex, usize>) {
-    esp_println::println!("writing...");
+    use core::fmt::Write;
     embedded_io_async::Write::write(
         &mut tx,
         b"Hello async serial. Enter something ended with EOT (CTRL-D).\r\n",
@@ -35,27 +36,30 @@ async fn writer(mut tx: UartTx<'static, UART0>) {
     .await
     .unwrap();
     embedded_io_async::Write::flush(&mut tx).await.unwrap();
+    loop {
+        let bytes_read = signal.wait().await;
+        signal.reset();
+        write!(&mut tx, "\r\n-- received {} bytes --\r\n", bytes_read).unwrap();
+        embedded_io_async::Write::flush(&mut tx).await.unwrap();
+    }
 }
 
 #[embassy_executor::task]
-async fn reader(mut rx: UartRx<'static, UART0>) {
+async fn reader(mut rx: UartRx<'static, UART0>, signal: &'static Signal<NoopRawMutex, usize>) {
-    esp_println::println!("reading...");
-    // max message size to receive
-    // leave some extra space for AT-CMD characters
     const MAX_BUFFER_SIZE: usize = 10 * READ_BUF_SIZE + 16;
 
-    let mut rbuf: Vec<u8, MAX_BUFFER_SIZE> = Vec::new();
+    let mut rbuf: [u8; MAX_BUFFER_SIZE] = [0u8; MAX_BUFFER_SIZE];
     let mut offset = 0;
-    while let Ok(len) = embedded_io_async::Read::read(&mut rx, &mut rbuf[offset..]).await {
+    loop {
-        offset += len;
+        let r = embedded_io_async::Read::read(&mut rx, &mut rbuf[offset..]).await;
-        if offset == 0 {
+        match r {
-            rbuf.truncate(0);
+            Ok(len) => {
-            break;
+                offset += len;
-        }
+                esp_println::println!("Read: {len}, data: {:?}", &rbuf[..offset]);
-        // if set_at_cmd is used than stop reading
+                offset = 0;
-        if len < READ_BUF_SIZE {
+                signal.signal(len);
-            rbuf.truncate(offset);
+            }
-            break;
+            Err(e) => esp_println::println!("RX Error: {:?}", e),
         }
     }
 }
@@ -74,10 +78,10 @@ async fn main(spawner: Spawner) {
     );
 
     #[cfg(feature = "embassy-time-timg0")]
-    embassy::init(
+    {
-        &clocks,
+        let timer_group0 = esp32c3_hal::timer::TimerGroup::new(peripherals.TIMG0, &clocks);
-        esp32c3_hal::timer::TimerGroup::new(peripherals.TIMG0, &clocks).timer0,
+        embassy::init(&clocks, timer_group0.timer0);
-    );
+    }
 
     let mut uart0 = Uart::new(peripherals.UART0, &clocks);
     uart0.set_at_cmd(AtCmdConfig::new(None, None, None, AT_CMD, None));
@@ -88,6 +92,8 @@ async fn main(spawner: Spawner) {
 
     interrupt::enable(Interrupt::UART0, interrupt::Priority::Priority1).unwrap();
 
-    spawner.spawn(reader(rx)).ok();
+    let signal = &*make_static!(Signal::new());
-    spawner.spawn(writer(tx)).ok();
+
+    spawner.spawn(reader(rx, &signal)).ok();
+    spawner.spawn(writer(tx, &signal)).ok();
 }

esp32c6-hal/Cargo.toml

@@ -53,6 +53,7 @@ hex-literal       = "0"
 elliptic-curve    = {version = "0.13.4", default-features = false, features = ["sec1"] }
 p192              = {version = "0.13.0", default-features = false, features = ["arithmetic"] }
 p256              = {version = "0.13.2", default-features = false, features = ["arithmetic"] }
+embassy-sync       = "0.2.0"
 
 [features]
 default              = ["rt", "vectored", "esp-hal-common/rv-zero-rtc-bss"]

esp32c6-hal/examples/embassy_serial.rs

@@ -8,6 +8,7 @@
 #![feature(type_alias_impl_trait)]
 
 use embassy_executor::Spawner;
+use embassy_sync::{blocking_mutex::raw::NoopRawMutex, signal::Signal};
 use esp32c6_hal::{
     clock::ClockControl,
     embassy,
@@ -18,7 +19,7 @@ use esp32c6_hal::{
 };
 use esp_backtrace as _;
 use esp_hal_common::uart::{config::AtCmdConfig, UartRx, UartTx};
-use heapless::Vec;
+use static_cell::make_static;
 
 // rx_fifo_full_threshold
 const READ_BUF_SIZE: usize = 64;
@@ -26,8 +27,8 @@ const READ_BUF_SIZE: usize = 64;
 const AT_CMD: u8 = 0x04;
 
 #[embassy_executor::task]
-async fn writer(mut tx: UartTx<'static, UART0>) {
+async fn writer(mut tx: UartTx<'static, UART0>, signal: &'static Signal<NoopRawMutex, usize>) {
-    esp_println::println!("writing...");
+    use core::fmt::Write;
     embedded_io_async::Write::write(
         &mut tx,
         b"Hello async serial. Enter something ended with EOT (CTRL-D).\r\n",
@@ -35,33 +36,36 @@ async fn writer(mut tx: UartTx<'static, UART0>) {
     .await
     .unwrap();
     embedded_io_async::Write::flush(&mut tx).await.unwrap();
+    loop {
+        let bytes_read = signal.wait().await;
+        signal.reset();
+        write!(&mut tx, "\r\n-- received {} bytes --\r\n", bytes_read).unwrap();
+        embedded_io_async::Write::flush(&mut tx).await.unwrap();
+    }
 }
 
 #[embassy_executor::task]
-async fn reader(mut rx: UartRx<'static, UART0>) {
+async fn reader(mut rx: UartRx<'static, UART0>, signal: &'static Signal<NoopRawMutex, usize>) {
-    esp_println::println!("reading...");
-    // max message size to receive
-    // leave some extra space for AT-CMD characters
     const MAX_BUFFER_SIZE: usize = 10 * READ_BUF_SIZE + 16;
 
-    let mut rbuf: Vec<u8, MAX_BUFFER_SIZE> = Vec::new();
+    let mut rbuf: [u8; MAX_BUFFER_SIZE] = [0u8; MAX_BUFFER_SIZE];
     let mut offset = 0;
-    while let Ok(len) = embedded_io_async::Read::read(&mut rx, &mut rbuf[offset..]).await {
+    loop {
-        offset += len;
+        let r = embedded_io_async::Read::read(&mut rx, &mut rbuf[offset..]).await;
-        if offset == 0 {
+        match r {
-            rbuf.truncate(0);
+            Ok(len) => {
-            break;
+                offset += len;
-        }
+                esp_println::println!("Read: {len}, data: {:?}", &rbuf[..offset]);
-        // if set_at_cmd is used than stop reading
+                offset = 0;
-        if len < READ_BUF_SIZE {
+                signal.signal(len);
-            rbuf.truncate(offset);
+            }
-            break;
+            Err(e) => esp_println::println!("RX Error: {:?}", e),
         }
     }
 }
 
 #[main]
-async fn main(spawner: Spawner) -> ! {
+async fn main(spawner: Spawner) {
     esp_println::println!("Init!");
     let peripherals = Peripherals::take();
     let system = peripherals.SYSTEM.split();
@@ -88,6 +92,8 @@ async fn main(spawner: Spawner) -> ! {
 
     interrupt::enable(Interrupt::UART0, interrupt::Priority::Priority1).unwrap();
 
-    spawner.spawn(reader(rx)).ok();
+    let signal = &*make_static!(Signal::new());
-    spawner.spawn(writer(tx)).ok();
+
+    spawner.spawn(reader(rx, &signal)).ok();
+    spawner.spawn(writer(tx, &signal)).ok();
 }

esp32h2-hal/Cargo.toml

@@ -53,6 +53,7 @@ hex-literal       = "0"
 elliptic-curve    = {version = "0.13.4", default-features = false, features = ["sec1"] }
 p192              = {version = "0.13.0", default-features = false, features = ["arithmetic"] }
 p256              = {version = "0.13.2", default-features = false, features = ["arithmetic"] }
+embassy-sync       = "0.2.0"
 
 [features]
 default              = ["rt", "vectored", "esp-hal-common/rv-zero-rtc-bss"]

esp32h2-hal/examples/embassy_serial.rs

@@ -8,6 +8,7 @@
 #![feature(type_alias_impl_trait)]
 
 use embassy_executor::Spawner;
+use embassy_sync::{blocking_mutex::raw::NoopRawMutex, signal::Signal};
 use esp32h2_hal::{
     clock::ClockControl,
     embassy,
@@ -18,7 +19,7 @@ use esp32h2_hal::{
 };
 use esp_backtrace as _;
 use esp_hal_common::uart::{config::AtCmdConfig, UartRx, UartTx};
-use heapless::Vec;
+use static_cell::make_static;
 
 // rx_fifo_full_threshold
 const READ_BUF_SIZE: usize = 64;
@@ -26,8 +27,8 @@ const READ_BUF_SIZE: usize = 64;
 const AT_CMD: u8 = 0x04;
 
 #[embassy_executor::task]
-async fn writer(mut tx: UartTx<'static, UART0>) {
+async fn writer(mut tx: UartTx<'static, UART0>, signal: &'static Signal<NoopRawMutex, usize>) {
-    esp_println::println!("writing...");
+    use core::fmt::Write;
     embedded_io_async::Write::write(
         &mut tx,
         b"Hello async serial. Enter something ended with EOT (CTRL-D).\r\n",
@@ -35,27 +36,30 @@ async fn writer(mut tx: UartTx<'static, UART0>) {
     .await
     .unwrap();
     embedded_io_async::Write::flush(&mut tx).await.unwrap();
+    loop {
+        let bytes_read = signal.wait().await;
+        signal.reset();
+        write!(&mut tx, "\r\n-- received {} bytes --\r\n", bytes_read).unwrap();
+        embedded_io_async::Write::flush(&mut tx).await.unwrap();
+    }
 }
 
 #[embassy_executor::task]
-async fn reader(mut rx: UartRx<'static, UART0>) {
+async fn reader(mut rx: UartRx<'static, UART0>, signal: &'static Signal<NoopRawMutex, usize>) {
-    esp_println::println!("reading...");
-    // max message size to receive
-    // leave some extra space for AT-CMD characters
     const MAX_BUFFER_SIZE: usize = 10 * READ_BUF_SIZE + 16;
 
-    let mut rbuf: Vec<u8, MAX_BUFFER_SIZE> = Vec::new();
+    let mut rbuf: [u8; MAX_BUFFER_SIZE] = [0u8; MAX_BUFFER_SIZE];
     let mut offset = 0;
-    while let Ok(len) = embedded_io_async::Read::read(&mut rx, &mut rbuf[offset..]).await {
+    loop {
-        offset += len;
+        let r = embedded_io_async::Read::read(&mut rx, &mut rbuf[offset..]).await;
-        if offset == 0 {
+        match r {
-            rbuf.truncate(0);
+            Ok(len) => {
-            break;
+                offset += len;
-        }
+                esp_println::println!("Read: {len}, data: {:?}", &rbuf[..offset]);
-        // if set_at_cmd is used than stop reading
+                offset = 0;
-        if len < READ_BUF_SIZE {
+                signal.signal(len);
-            rbuf.truncate(offset);
+            }
-            break;
+            Err(e) => esp_println::println!("RX Error: {:?}", e),
         }
     }
 }
@@ -88,6 +92,8 @@ async fn main(spawner: Spawner) {
 
     interrupt::enable(Interrupt::UART0, interrupt::Priority::Priority1).unwrap();
 
-    spawner.spawn(reader(rx)).ok();
+    let signal = &*make_static!(Signal::new());
-    spawner.spawn(writer(tx)).ok();
+
+    spawner.spawn(reader(rx, &signal)).ok();
+    spawner.spawn(writer(tx, &signal)).ok();
 }

esp32s2-hal/examples/embassy_serial.rs

@@ -8,9 +8,10 @@
 #![feature(type_alias_impl_trait)]
 
 use embassy_executor::Spawner;
+use embassy_sync::{blocking_mutex::raw::NoopRawMutex, signal::Signal};
 use esp32s2_hal::{
     clock::ClockControl,
-    embassy::{self},
+    embassy,
     interrupt,
     peripherals::{Interrupt, Peripherals, UART0},
     prelude::*,
@@ -18,7 +19,7 @@ use esp32s2_hal::{
 };
 use esp_backtrace as _;
 use esp_hal_common::uart::{config::AtCmdConfig, UartRx, UartTx};
-use heapless::Vec;
+use static_cell::make_static;
 
 // rx_fifo_full_threshold
 const READ_BUF_SIZE: usize = 64;
@@ -26,8 +27,8 @@ const READ_BUF_SIZE: usize = 64;
 const AT_CMD: u8 = 0x04;
 
 #[embassy_executor::task]
-async fn writer(mut tx: UartTx<'static, UART0>) {
+async fn writer(mut tx: UartTx<'static, UART0>, signal: &'static Signal<NoopRawMutex, usize>) {
-    esp_println::println!("writing...");
+    use core::fmt::Write;
     embedded_io_async::Write::write(
         &mut tx,
         b"Hello async serial. Enter something ended with EOT (CTRL-D).\r\n",
@@ -35,27 +36,30 @@ async fn writer(mut tx: UartTx<'static, UART0>) {
     .await
     .unwrap();
     embedded_io_async::Write::flush(&mut tx).await.unwrap();
+    loop {
+        let bytes_read = signal.wait().await;
+        signal.reset();
+        write!(&mut tx, "\r\n-- received {} bytes --\r\n", bytes_read).unwrap();
+        embedded_io_async::Write::flush(&mut tx).await.unwrap();
+    }
 }
 
 #[embassy_executor::task]
-async fn reader(mut rx: UartRx<'static, UART0>) {
+async fn reader(mut rx: UartRx<'static, UART0>, signal: &'static Signal<NoopRawMutex, usize>) {
-    esp_println::println!("reading...");
-    // max message size to receive
-    // leave some extra space for AT-CMD characters
     const MAX_BUFFER_SIZE: usize = 10 * READ_BUF_SIZE + 16;
 
-    let mut rbuf: Vec<u8, MAX_BUFFER_SIZE> = Vec::new();
+    let mut rbuf: [u8; MAX_BUFFER_SIZE] = [0u8; MAX_BUFFER_SIZE];
     let mut offset = 0;
-    while let Ok(len) = embedded_io_async::Read::read(&mut rx, &mut rbuf[offset..]).await {
+    loop {
-        offset += len;
+        let r = embedded_io_async::Read::read(&mut rx, &mut rbuf[offset..]).await;
-        if offset == 0 {
+        match r {
-            rbuf.truncate(0);
+            Ok(len) => {
-            break;
+                offset += len;
-        }
+                esp_println::println!("Read: {len}, data: {:?}", &rbuf[..offset]);
-        // if set_at_cmd is used than stop reading
+                offset = 0;
-        if len < READ_BUF_SIZE {
+                signal.signal(len);
-            rbuf.truncate(offset);
+            }
-            break;
+            Err(e) => esp_println::println!("RX Error: {:?}", e),
         }
     }
 }
@@ -88,6 +92,8 @@ async fn main(spawner: Spawner) {
 
     interrupt::enable(Interrupt::UART0, interrupt::Priority::Priority1).unwrap();
 
-    spawner.spawn(reader(rx)).ok();
+    let signal = &*make_static!(Signal::new());
-    spawner.spawn(writer(tx)).ok();
+
+    spawner.spawn(reader(rx, &signal)).ok();
+    spawner.spawn(writer(tx, &signal)).ok();
 }

esp32s3-hal/examples/embassy_serial.rs

@@ -8,9 +8,10 @@
 #![feature(type_alias_impl_trait)]
 
 use embassy_executor::Spawner;
+use embassy_sync::{blocking_mutex::raw::NoopRawMutex, signal::Signal};
 use esp32s3_hal::{
     clock::ClockControl,
-    embassy::{self},
+    embassy,
     interrupt,
     peripherals::{Interrupt, Peripherals, UART0},
     prelude::*,
@@ -18,7 +19,7 @@ use esp32s3_hal::{
 };
 use esp_backtrace as _;
 use esp_hal_common::uart::{config::AtCmdConfig, UartRx, UartTx};
-use heapless::Vec;
+use static_cell::make_static;
 
 // rx_fifo_full_threshold
 const READ_BUF_SIZE: usize = 64;
@@ -26,8 +27,8 @@ const READ_BUF_SIZE: usize = 64;
 const AT_CMD: u8 = 0x04;
 
 #[embassy_executor::task]
-async fn writer(mut tx: UartTx<'static, UART0>) {
+async fn writer(mut tx: UartTx<'static, UART0>, signal: &'static Signal<NoopRawMutex, usize>) {
-    esp_println::println!("writing...");
+    use core::fmt::Write;
     embedded_io_async::Write::write(
         &mut tx,
         b"Hello async serial. Enter something ended with EOT (CTRL-D).\r\n",
@@ -35,27 +36,30 @@ async fn writer(mut tx: UartTx<'static, UART0>) {
     .await
     .unwrap();
     embedded_io_async::Write::flush(&mut tx).await.unwrap();
+    loop {
+        let bytes_read = signal.wait().await;
+        signal.reset();
+        write!(&mut tx, "\r\n-- received {} bytes --\r\n", bytes_read).unwrap();
+        embedded_io_async::Write::flush(&mut tx).await.unwrap();
+    }
 }
 
 #[embassy_executor::task]
-async fn reader(mut rx: UartRx<'static, UART0>) {
+async fn reader(mut rx: UartRx<'static, UART0>, signal: &'static Signal<NoopRawMutex, usize>) {
-    esp_println::println!("reading...");
-    // max message size to receive
-    // leave some extra space for AT-CMD characters
     const MAX_BUFFER_SIZE: usize = 10 * READ_BUF_SIZE + 16;
 
-    let mut rbuf: Vec<u8, MAX_BUFFER_SIZE> = Vec::new();
+    let mut rbuf: [u8; MAX_BUFFER_SIZE] = [0u8; MAX_BUFFER_SIZE];
     let mut offset = 0;
-    while let Ok(len) = embedded_io_async::Read::read(&mut rx, &mut rbuf[offset..]).await {
+    loop {
-        offset += len;
+        let r = embedded_io_async::Read::read(&mut rx, &mut rbuf[offset..]).await;
-        if offset == 0 {
+        match r {
-            rbuf.truncate(0);
+            Ok(len) => {
-            break;
+                offset += len;
-        }
+                esp_println::println!("Read: {len}, data: {:?}", &rbuf[..offset]);
-        // if set_at_cmd is used than stop reading
+                offset = 0;
-        if len < READ_BUF_SIZE {
+                signal.signal(len);
-            rbuf.truncate(offset);
+            }
-            break;
+            Err(e) => esp_println::println!("RX Error: {:?}", e),
         }
     }
 }
@@ -88,6 +92,8 @@ async fn main(spawner: Spawner) {
 
     interrupt::enable(Interrupt::UART0, interrupt::Priority::Priority1).unwrap();
 
-    spawner.spawn(reader(rx)).ok();
+    let signal = &*make_static!(Signal::new());
-    spawner.spawn(writer(tx)).ok();
+
+    spawner.spawn(reader(rx, &signal)).ok();
+    spawner.spawn(writer(tx, &signal)).ok();
 }