[][src]Trait kernel::hil::spi::SpiMaster

pub trait SpiMaster {
    type ChipSelect: Copy;
    fn set_client(&self, client: &'static dyn SpiMasterClient);
fn init(&self);
fn is_busy(&self) -> bool;
fn read_write_bytes(
        write_buffer: &'static mut [u8],
        read_buffer: Option<&'static mut [u8]>,
        len: usize
    ) -> ReturnCode;
fn write_byte(&self, val: u8);
fn read_byte(&self) -> u8;
fn read_write_byte(&self, val: u8) -> u8;
fn specify_chip_select(&self, cs: Self::ChipSelect);
fn set_rate(&self, rate: u32) -> u32;
fn get_rate(&self) -> u32;
fn set_clock(&self, polarity: ClockPolarity);
fn get_clock(&self) -> ClockPolarity;
fn set_phase(&self, phase: ClockPhase);
fn get_phase(&self) -> ClockPhase;
fn hold_low(&self);
fn release_low(&self); }

The SpiMaster trait for interacting with SPI slave devices at a byte or buffer level.

Using SpiMaster normally involves three steps:

  1. Configure the SPI bus for a peripheral 1a. Call set_chip_select to select which peripheral and turn on SPI 1b. Call set operations as needed to configure bus NOTE: You MUST select the chip select BEFORE configuring SPI settings.
  2. Invoke read, write, read_write on SpiMaster 3a. Call clear_chip_select to turn off bus, or 3b. Call set_chip_select to choose another peripheral, go to step 1b or 2.

This interface assumes that the SPI configuration for a particular peripheral persists across chip select. For example, with this set of calls:

specify_chip_select(1); set_phase(SampleLeading); specify_chip_select(2); set_phase(SampleTrailing); specify_chip_select(1); write_byte(0); // Uses SampleLeading

If additional chip selects are needed, they can be performed with GPIO and manual re-initialization of settings.

specify_chip_select(0); set_phase(SampleLeading); pin_a.set(); write_byte(0xaa); // Uses SampleLeading pin_a.clear(); set_phase(SampleTrailing); pin_b.set(); write_byte(0xaa); // Uses SampleTrailing

Associated Types

type ChipSelect: Copy

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Required methods

fn set_client(&self, client: &'static dyn SpiMasterClient)

fn init(&self)

fn is_busy(&self) -> bool

fn read_write_bytes(
    write_buffer: &'static mut [u8],
    read_buffer: Option<&'static mut [u8]>,
    len: usize
) -> ReturnCode

Perform an asynchronous read/write operation, whose completion is signaled by invoking SpiMasterClient on the initialized client. write_buffer must be Some, read_buffer may be None. If read_buffer is Some, the length of the operation is the minimum of the size of the two buffers.

fn write_byte(&self, val: u8)

fn read_byte(&self) -> u8

fn read_write_byte(&self, val: u8) -> u8

fn specify_chip_select(&self, cs: Self::ChipSelect)

Tell the SPI peripheral what to use as a chip select pin. The type of the argument is based on what makes sense for the peripheral when this trait is implemented.

fn set_rate(&self, rate: u32) -> u32

Returns the actual rate set

fn get_rate(&self) -> u32

fn set_clock(&self, polarity: ClockPolarity)

fn get_clock(&self) -> ClockPolarity

fn set_phase(&self, phase: ClockPhase)

fn get_phase(&self) -> ClockPhase

fn hold_low(&self)

fn release_low(&self)

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