embassy/embassy-traits/src/spi.rs

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//! Async SPI API
use core::future::Future;
/// Full duplex (master mode)
///
/// # Notes
///
/// - It's the task of the user of this interface to manage the slave select lines
///
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/// - Due to how full duplex SPI works each `read` call must be preceded by a `write` call.
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///
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/// - `read` calls only return the data received with the last `write` call.
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/// Previously received data is discarded
///
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/// - Data is only guaranteed to be clocked out when the `read` call succeeds.
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/// The slave select line shouldn't be released before that.
///
/// - Some SPIs can work with 8-bit *and* 16-bit words. You can overload this trait with different
/// `Word` types to allow operation in both modes.
pub trait FullDuplex<Word> {
/// An enumeration of SPI errors
type Error;
type WriteFuture<'a>: Future<Output = Result<(), Self::Error>> + 'a;
type ReadFuture<'a>: Future<Output = Result<(), Self::Error>> + 'a;
type WriteReadFuture<'a>: Future<Output = Result<(), Self::Error>> + 'a;
fn read<'a>(&'a mut self, data: &'a mut [Word]) -> Self::ReadFuture<'_>;
fn write<'a>(&'a mut self, data: &'a [Word]) -> Self::WriteFuture<'_>;
fn read_write<'a>(
&mut self,
read: &'a mut [Word],
write: &'a [Word],
) -> Self::WriteReadFuture<'_>;
}