Struct DmaTxStreamBuf 

pub struct DmaTxStreamBuf { /* private fields */ }

Available on crate feature unstable only.

DMA Streaming Transmit Buffer.

This is symmetric implementation to DmaRxStreamBuf, used for continuously streaming data to a peripheral’s FIFO.

The list starts out like so A(full) -> B(full) -> C(full) -> D(full) -> NULL.

As the DMA writes to FIFO, the list progresses like so:

• A(full) -> B(full) -> C(full) -> D(full) -> NULL
• A(empty) -> B(full) -> C(full) -> D(full) -> NULL
• A(empty) -> B(empty) -> C(full) -> D(full) -> NULL
• A(empty) -> B(empty) -> C(empty) -> D(full) -> NULL

As you call DmaTxStreamBufView::push the list (approximately) progresses like so:

• A(empty) -> B(empty) -> C(empty) -> D(full) -> NULL
• B(empty) -> C(empty) -> D(full) -> A(full) -> NULL
• C(empty) -> D(full) -> A(full) -> B(full) -> NULL
• D(full) -> A(full) -> B(full) -> C(full) -> NULL

If all the descriptors run out, the DmaTxInterrupt::TotalEof interrupt will fire and DMA will stop writing, at which point it is up to you to resume/restart the transfer.

Implementations

impl DmaTxStreamBuf

pub fn new( descriptors: DmaAlignedMut<'static, [DmaDescriptor]>, buffer: DmaAlignedMut<'static, [u8]>, ) -> Result<Self, DmaBufError>

Creates a new DmaTxStreamBuf evenly distributing the buffer between the provided descriptors.

pub fn split( self, ) -> (DmaAlignedMut<'static, [DmaDescriptor]>, DmaAlignedMut<'static, [u8]>)

Consume the buf, returning the descriptors and buffer.

pub fn push(&mut self, data: &[u8]) -> usize

Push the buffer with the given data before DMA transfer starts.

It’s expected to pre-fill at least enough data to fill the first two descriptors’ buffers. The more data is pre-filled, the more head-room is left to push more data.

pub fn push_with(&mut self, f: impl FnOnce(&mut [u8]) -> usize) -> usize

Push the buffer with the given data before DMA transfer starts.

It’s expected to pre-fill at least enough data to fill the first two descriptors’ buffers. The more data is pre-filled, the more head-room is left to push more data.

Returns the number of bytes filled.

Trait Implementations

impl Debug for DmaTxStreamBuf

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

Formats the value using the given formatter.

impl DmaTxBuffer for DmaTxStreamBuf

type View = DmaTxStreamBufView

A type providing operations that are safe to perform on the buffer whilst the DMA is actively using it.

type Final = DmaTxStreamBuf

The type returned to the user when a transfer finishes.

fn prepare(&mut self) -> Preparation

Prepares the buffer for an imminent transfer and returns information required to use this buffer.

fn into_view(self) -> Self::View

This is called before the DMA starts using the buffer.

fn from_view(view: Self::View) -> Self

This is called after the DMA is done using the buffer.