Trait grand_central_m4::sercom::v2::spi::Length[−][src]

pub trait Length: 'static + Sealed + Unsigned {
    type Word: 'static;
    fn configure(sercom: &RegisterBlock) { ... }
}
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 corresponding word size.

As mentioned in the OpMode documentation, this module chooses to always operate in 32-bit extension mode. The LENGTH counter is used to control the number of byes in each SPI transaction.

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. The static Length types can be imported from the lengths submodule.

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 behave differently than longer transaction lengths.

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].

Provided methods

Configure the LENGTH register and enable the LENGTH counter

Implementations on Foreign Types

Implementors