Struct CanFdTx 

pub struct CanFdTx<'a, Dm: DriverMode> { /* private fields */ }

Transmitting half of a split controller.

See CanFd::split.

Implementations

impl<Dm: DriverMode> CanFdTx<'_, Dm>

pub fn tx_buffer_count(&self) -> u8

Returns the number of TX buffers the hardware provides.

pub fn transmit(&mut self, frame: &Frame) -> Result<u8, Error>

Queues a frame in the first free TX buffer and arms it.

Returns the index of the buffer used. Up to CanFdTx::tx_buffer_count frames can be queued at once.

The hardware picks the next frame to send among the armed buffers by priority, and among equal priorities by the lower buffer index; see CanFdTx::set_tx_priority. The order in which frames were queued plays no part in that choice. With equal priorities a frame queued into a buffer that a finished frame freed up is sent before frames still waiting in higher-numbered buffers. To keep frames in the order they were queued, wait for each buffer to leave TxBufferState::Ready before queueing the next frame, or give later frames lower priorities.

Errors

Error::ControllerStopped when the controller is not on the bus. A stopped controller ignores the command that arms a buffer, so the frame would be lost.

Error::NoFreeTxBuffer when every TX buffer is occupied.

pub fn tx_buffer_state(&self, index: u8) -> TxBufferState

Returns the state of one TX buffer.

Returns TxBufferState::NotExist for an index the hardware does not have.

pub fn abort_transmit(&mut self, index: u8)

Requests that a queued transmission be aborted.

Does nothing for an index the hardware does not have.

pub fn release_tx_buffer(&mut self, index: u8)

Returns a TX buffer to the empty state, releasing it for reuse.

Does nothing for an index the hardware does not have.

pub fn set_tx_priority(&mut self, index: u8, priority: u8)

Sets a TX buffer’s arbitration priority.

Higher values win. Equal priorities are resolved in favor of the lower buffer index (TRM 38.3.8.1). A value above MAX_TX_PRIORITY counts as that maximum. Does nothing for an index the hardware does not have.

The priority belongs to the buffer, not to the frame in it, and all buffers start out equal. Set it before arming the buffer with CanFdTx::transmit, or right after, while the frame is still TxBufferState::Ready.

pub fn error_state(&self) -> ErrorState

Returns the current fault confinement state; see CanFd::error_state.

On bus-off every armed TX buffer fails, so a transmission that ends in Error::TransmitFailed can be told apart from an exhausted retransmission limit here.

pub fn receive_error_count(&self) -> u16

Returns the receive error counter.

pub fn transmit_error_count(&self) -> u16

Returns the transmit error counter.

pub fn request_bus_off_recovery(&mut self)

Requests that a bus-off controller rejoin the bus.

Does nothing unless the controller is bus-off. Rejoining takes 128 occurrences of 11 recessive bits, as ISO 11898-1 requires. Leaving the bus with CanFd::stop and joining it again with CanFd::start also clears the bus-off state, after ordinary integration.

The state is checked here because the hardware remembers a request made while error-active and then rejoins on its own the next time it goes bus-off (measured on an ESP32-C5; TRM register 38.3 says otherwise).

impl CanFdTx<'_, Async>

pub async fn transmit_async(&mut self, frame: &Frame) -> Result<(), Error>

Queues a frame and waits until the hardware finishes with it.

Errors

Error::ControllerStopped when the controller is not on the bus, and Error::NoFreeTxBuffer when every TX buffer is occupied; see CanFdTx::transmit.

Error::TransmitFailed when the controller gave up on the frame.

Error::TransmitAborted when the transmission was aborted.

Cancellation Safety

This future is not cancel-safe. Dropping it leaves the frame queued, and the hardware may still transmit it.

Trait Implementations

impl<Dm: DriverMode> Debug for CanFdTx<'_, Dm>

Available on crate feature unstable only.

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.