Add TWAI support for ESP32 and ESP32-S2

esp-hal-common/build.rs

@@ -39,6 +39,7 @@ fn main() {
     //   - 'systimer'
     //   - 'timg0'
     //   - 'timg1'
+    //   - 'twai'
     //   - 'uart2'
     //   - 'usb_otg'
     //   - 'usb_serial_jtag'
@@ -59,6 +60,7 @@ fn main() {
             "spi3",
             "timg0",
             "timg1",
+            "twai",
             "uart2",
         ]
     } else if esp32c2 {
@@ -82,6 +84,7 @@ fn main() {
             "systimer",
             "timg0",
             "timg1",
+            "twai",
             "usb_serial_jtag",
         ]
     } else if esp32s2 {
@@ -98,6 +101,7 @@ fn main() {
             "systimer",
             "timg0",
             "timg1",
+            "twai",
             "usb_otg",
         ]
     } else if esp32s3 {
@@ -114,6 +118,7 @@ fn main() {
             "systimer",
             "timg0",
             "timg1",
+            "twai",
             "uart2",
             "usb_otg",
             "usb_serial_jtag",

esp-hal-common/src/gpio/esp32.rs

@@ -167,7 +167,7 @@ pub enum InputSignal {
     RMT_SIG_6             = 89,
     RMT_SIG_7             = 90,
     EXT_ADC_START         = 93,
-    CAN_RX                = 94,
+    TWAI_RX               = 94,
     I2CEXT1_SCL           = 95,
     I2CEXT1_SDA           = 96,
     HOST_CARD_DETECT_N_1  = 97,
@@ -198,7 +198,7 @@ pub enum InputSignal {
     PWM3_CAP1             = 122,
     PWM3_CAP2             = 123,
     PWM3_CAP3             = 124,
-    CAN_CLKOUT            = 125,
+    TWAI_CLKOUT           = 125,
     SPID4                 = 128,
     SPID5                 = 129,
     SPID6                 = 130,
@@ -422,8 +422,8 @@ pub enum OutputSignal {
     PWM2_3L                  = 119,
     PWM2_4H                  = 120,
     PWM2_4L                  = 121,
-    CAN_TX                   = 123,
-    CAN_BUS_OFF_ON           = 124,
+    TWAI_TX                  = 123,
+    TWAI_BUS_OFF_ON          = 124,
     SPID4                    = 128,
     SPID5                    = 129,
     SPID6                    = 130,

esp-hal-common/src/gpio/esp32s2.rs

@@ -128,6 +128,7 @@ pub enum InputSignal {
     FSPIIO6           = 115,
     FSPIIO7           = 116,
     FSPICS0           = 117,
+    TWAI_RX           = 123,
     SUBSPIQ           = 127,
     SUBSPID           = 128,
     SUBSPIHD          = 129,
@@ -215,6 +216,7 @@ pub enum OutputSignal {
     FSPICS3          = 120,
     FSPICS4          = 121,
     FSPICS5          = 122,
+    TWAI_TX          = 123,
     SUBSPICLK        = 126,
     SUBSPIQ          = 127,
     SUBSPID          = 128,

esp-hal-common/src/lib.rs

@@ -73,7 +73,7 @@ pub mod system;
 #[cfg(systimer)]
 pub mod systimer;
 pub mod timer;
-#[cfg(any(esp32s3, esp32c3))]
+#[cfg(twai)]
 pub mod twai;
 pub mod uart;
 #[cfg(usb_serial_jtag)]

esp-hal-common/src/system.rs

@@ -42,7 +42,7 @@ pub enum Peripheral {
     I2s1,
     #[cfg(usb_otg)]
     Usb,
-    #[cfg(any(esp32s3, esp32c3))]
+    #[cfg(twai)]
     Twai,
 }
 
@@ -151,7 +151,7 @@ impl PeripheralClockControl {
                 perip_clk_en0.modify(|_, w| w.usb_clk_en().set_bit());
                 perip_rst_en0.modify(|_, w| w.usb_rst().clear_bit());
             }
-            #[cfg(any(esp32s3, esp32c3))]
+            #[cfg(twai)]
             Peripheral::Twai => {
                 perip_clk_en0.modify(|_, w| w.twai_clk_en().set_bit());
                 perip_rst_en0.modify(|_, w| w.twai_rst().clear_bit());

esp-hal-common/src/twai/mod.rs

@@ -705,7 +705,6 @@ pub trait Instance {
     fn register_block(&self) -> &RegisterBlock;
 }
 
-#[cfg(any(esp32s3, esp32c3))]
 impl Instance for crate::peripherals::TWAI {
     #[inline(always)]
     fn register_block(&self) -> &RegisterBlock {

esp32-hal/Cargo.toml

@@ -26,6 +26,7 @@ categories = [
 
 [dependencies]
 embassy-time       = { version = "0.1.0", features = ["nightly"], optional = true }
+embedded-can       = { version = "0.4.1", optional = true }
 embedded-hal       = { version = "0.2.7",  features = ["unproven"] }
 embedded-hal-1     = { version = "=1.0.0-alpha.9", optional = true, package = "embedded-hal" }
 embedded-hal-async = { version = "0.1.0-alpha.3", optional = true }
@@ -48,7 +49,7 @@ static_cell       = "1.0.0"
 [features]
 default           = ["rt", "vectored"]
 bluetooth         = []
-eh1               = ["esp-hal-common/eh1", "dep:embedded-hal-1", "dep:embedded-hal-nb"]
+eh1               = ["dep:embedded-can", "esp-hal-common/eh1", "dep:embedded-hal-1", "dep:embedded-hal-nb"]
 rt                = ["xtensa-lx-rt/esp32"]
 smartled          = ["esp-hal-common/smartled"]
 ufmt              = ["esp-hal-common/ufmt"]

esp32-hal/examples/twai.rs

@@ -0,0 +1,110 @@
+//! This example sends a CAN message to another ESP and receives it back.
+//!
+//! Wiring:
+//! This example works without CAN Transceivers by:
+//! * setting the tx pins to open drain
+//! * connecting all rx and tx pins together
+//! * adding a pull-up to the signal pins
+//!
+//! ESP1/GND --- ESP2/GND
+//! ESP1/IO2 --- ESP1/IO4 --- ESP2/IO2 --- ESP2/IO4 --- 4.8kOhm --- ESP1/5V
+//!
+//! `IS_FIRST_SENDER` below must be set to false on one of the ESP's
+
+#![no_std]
+#![no_main]
+
+const IS_FIRST_SENDER: bool = true;
+
+// Run this example with the eh1 feature enabled to use embedded-can instead of
+// embedded-hal-0.2.7. embedded-can was split off from embedded-hal before it's
+// upgrade to 1.0.0. cargo run --example twai --features eh1 --release
+#[cfg(feature = "eh1")]
+use embedded_can::{nb::Can, Frame, StandardId};
+// Run this example without the eh1 flag to use the embedded-hal 0.2.7 CAN traits.
+// cargo run --example twai --release
+#[cfg(not(feature = "eh1"))]
+use embedded_hal::can::{Can, Frame, StandardId};
+use esp32_hal::{
+    clock::ClockControl,
+    gpio::IO,
+    peripherals::Peripherals,
+    prelude::*,
+    timer::TimerGroup,
+    twai,
+    Rtc,
+};
+use esp_backtrace as _;
+use esp_println::println;
+use nb::block;
+use xtensa_lx_rt::entry;
+
+#[entry]
+fn main() -> ! {
+    let peripherals = Peripherals::take();
+    let mut system = peripherals.DPORT.split();
+    let clocks = ClockControl::boot_defaults(system.clock_control).freeze();
+
+    let timer_group0 = TimerGroup::new(peripherals.TIMG0, &clocks);
+    let mut wdt = timer_group0.wdt;
+    let mut rtc = Rtc::new(peripherals.RTC_CNTL);
+
+    // Disable MWDT and RWDT (Watchdog) flash boot protection
+    wdt.disable();
+    rtc.rwdt.disable();
+
+    let io = IO::new(peripherals.GPIO, peripherals.IO_MUX);
+
+    // Set the tx pin as open drain. Skip this if using transceivers.
+    let can_tx_pin = io.pins.gpio2.into_open_drain_output();
+    let can_rx_pin = io.pins.gpio4;
+
+    // The speed of the CAN bus.
+    const CAN_BAUDRATE: twai::BaudRate = twai::BaudRate::B1000K;
+
+    // Begin configuring the TWAI peripheral. The peripheral is in a reset like
+    // state that prevents transmission but allows configuration.
+    let mut can_config = twai::TwaiConfiguration::new(
+        peripherals.TWAI,
+        can_tx_pin,
+        can_rx_pin,
+        &mut system.peripheral_clock_control,
+        &clocks,
+        CAN_BAUDRATE,
+    );
+
+    // Partially filter the incoming messages to reduce overhead of receiving
+    // undesired messages. Note that due to how the hardware filters messages,
+    // standard ids and extended ids may both match a filter. Frame ids should
+    // be explicitly checked in the application instead of fully relying on
+    // these partial acceptance filters to exactly match.
+    // A filter that matches StandardId::ZERO.
+    const FILTER: twai::filter::SingleStandardFilter =
+        twai::filter::SingleStandardFilter::new(b"00000000000", b"x", [b"xxxxxxxx", b"xxxxxxxx"]);
+    can_config.set_filter(FILTER);
+
+    // Start the peripheral. This locks the configuration settings of the peripheral
+    // and puts it into operation mode, allowing packets to be sent and
+    // received.
+    let mut can = can_config.start();
+
+    if IS_FIRST_SENDER {
+        // Send a frame to the other ESP
+        let frame = Frame::new(StandardId::ZERO, &[1, 2, 3]).unwrap();
+        block!(can.transmit(&frame)).unwrap();
+        println!("Sent a frame");
+    }
+
+    // Wait for a frame to be received.
+    let frame = block!(can.receive()).unwrap();
+
+    println!("Received a frame: {frame:?}");
+
+    if !IS_FIRST_SENDER {
+        // Transmit the frame back to the other ESP
+        block!(can.transmit(&frame)).unwrap();
+        println!("Sent a frame");
+    }
+
+    loop {}
+}

esp32-hal/src/lib.rs

@@ -26,6 +26,7 @@ pub use esp_hal_common::{
     spi,
     system,
     timer,
+    twai,
     uart,
     utils,
     Cpu,

esp32c3-hal/examples/twai.rs

@@ -1,15 +1,30 @@
+//! This example sends a CAN message to another ESP and receives it back.
+//!
+//! Wiring:
+//! This example works without CAN Transceivers by:
+//! * setting the tx pins to open drain
+//! * connecting all rx and tx pins together
+//! * adding a pull-up to the signal pins
+//!
+//! ESP1/GND --- ESP2/GND
+//! ESP1/IO2 --- ESP1/IO3 --- ESP2/IO2 --- ESP2/IO3 --- 4.8kOhm --- ESP1/5V
+//!
+//! `IS_FIRST_SENDER` below must be set to false on one of the ESP's
+
 #![no_std]
 #![no_main]
 
+const IS_FIRST_SENDER: bool = true;
+
 // Run this example with the eh1 feature enabled to use embedded-can instead of
 // embedded-hal-0.2.7. embedded-can was split off from embedded-hal before it's
 // upgrade to 1.0.0. cargo run --example twai --features eh1 --release
 #[cfg(feature = "eh1")]
-use embedded_can::{nb::Can, Frame, Id};
+use embedded_can::{nb::Can, Frame, StandardId};
 // Run this example without the eh1 flag to use the embedded-hal 0.2.7 CAN traits.
 // cargo run --example twai --release
 #[cfg(not(feature = "eh1"))]
-use embedded_hal::can::{Can, Frame, Id};
+use embedded_hal::can::{Can, Frame, StandardId};
 use esp32c3_hal::{
     clock::ClockControl,
     gpio::IO,
@@ -44,9 +59,8 @@ fn main() -> ! {
 
     let io = IO::new(peripherals.GPIO, peripherals.IO_MUX);
 
-    // Use GPIO pins 2 and 3 to connect to the respective pins on the CAN
-    // transceiver.
-    let can_tx_pin = io.pins.gpio2;
+    // Set the tx pin as open drain. Skip this if using transceivers.
+    let can_tx_pin = io.pins.gpio2.into_open_drain_output();
     let can_rx_pin = io.pins.gpio3;
 
     // The speed of the CAN bus.
@@ -67,42 +81,34 @@ fn main() -> ! {
     // undesired messages. Note that due to how the hardware filters messages,
     // standard ids and extended ids may both match a filter. Frame ids should
     // be explicitly checked in the application instead of fully relying on
-    // these partial acceptance filters to exactly match. A filter that matches
-    // standard ids of an even value.
+    // these partial acceptance filters to exactly match.
+    // A filter that matches StandardId::ZERO.
     const FILTER: twai::filter::SingleStandardFilter =
-        twai::filter::SingleStandardFilter::new(b"xxxxxxxxxx0", b"x", [b"xxxxxxxx", b"xxxxxxxx"]);
+        twai::filter::SingleStandardFilter::new(b"00000000000", b"x", [b"xxxxxxxx", b"xxxxxxxx"]);
     can_config.set_filter(FILTER);
 
     // Start the peripheral. This locks the configuration settings of the peripheral
     // and puts it into operation mode, allowing packets to be sent and
     // received.
     let mut can = can_config.start();
 
-    loop {
-        // Wait for a frame to be received.
-        let frame = block!(can.receive()).unwrap();
-
-        println!("Received a frame:");
-
-        // Print different messages based on the frame id type.
-        match frame.id() {
-            Id::Standard(id) => {
-                println!("\tStandard Id: {:?}", id);
-            }
-            Id::Extended(id) => {
-                println!("\tExtended Id: {:?}", id);
-            }
-        }
-
-        // Print out the frame data or the requested data length code for a remote
-        // transmission request frame.
-        if frame.is_data_frame() {
-            println!("\tData: {:?}", frame.data());
-        } else {
-            println!("\tRemote Frame. Data Length Code: {}", frame.dlc());
-        }
-
-        // Transmit the frame back.
-        let _result = block!(can.transmit(&frame)).unwrap();
+    if IS_FIRST_SENDER {
+        // Send a frame to the other ESP
+        let frame = Frame::new(StandardId::ZERO, &[1, 2, 3]).unwrap();
+        block!(can.transmit(&frame)).unwrap();
+        println!("Sent a frame");
     }
+
+    // Wait for a frame to be received.
+    let frame = block!(can.receive()).unwrap();
+
+    println!("Received a frame: {frame:?}");
+
+    if !IS_FIRST_SENDER {
+        // Transmit the frame back to the other ESP
+        block!(can.transmit(&frame)).unwrap();
+        println!("Sent a frame");
+    }
+
+    loop {}
 }

esp32s2-hal/Cargo.toml

@@ -26,6 +26,7 @@ categories = [
 
 [dependencies]
 embassy-time       = { version = "0.1.0", features = ["nightly"], optional = true }
+embedded-can       = { version = "0.4.1", optional = true }
 embedded-hal       = { version = "0.2.7",  features = ["unproven"] }
 embedded-hal-1     = { version = "=1.0.0-alpha.9", optional = true, package = "embedded-hal" }
 embedded-hal-async = { version = "0.1.0-alpha.3", optional = true }
@@ -50,7 +51,7 @@ static_cell       = "1.0.0"
 
 [features]
 default   = ["rt", "vectored"]
-eh1       = ["esp-hal-common/eh1", "dep:embedded-hal-1", "dep:embedded-hal-nb"]
+eh1       = ["dep:embedded-can", "esp-hal-common/eh1", "dep:embedded-hal-1", "dep:embedded-hal-nb"]
 rt        = ["xtensa-lx-rt/esp32s2"]
 smartled  = ["esp-hal-common/smartled"]
 ufmt      = ["esp-hal-common/ufmt"]