Trait atsamd_hal::sercom::spi::Length

source · [−]
pub trait Length: Sealed + Unsigned + 'static {
    type Word: 'static;
}
Expand description

Type-level enum representing the SPI transaction length, in bytes

This trait acts as both a type-level enum, forming a type class for transaction lengths, as well as a type-level function mapping the Length to the corresponding Word size.

The SPI transaction length is represented in the type domain using Unsigned types from the typenum crate. The length can be set statically, using a length from U1 to U255, or it can be set dynamically, using the DynLength marker type. All valid Length types are re-exported in this module.

The SPI transaction length affects the word size for the embedded HAL traits, as well as other aspects of the SPI API. Transaction lengths of 1-4 only require a single read/write of the DATA register, so they have an AtomicSize behave differently than longer transaction lengths.

Required Associated Types

Word size for the transaction length

For lengths 1-4, this type is u8, u16 or u32. For longer transactions, this type is [u8, Self::USIZE].

Implementors