Struct I2cScript 

pub struct I2cScript { /* private fields */ }

An I2C bus that plays a script of transfers and replies.

Each transaction the driver issues is matched against the next step. A register read (a write followed by a read in one transaction) consumes one I2cStep::WriteRead; a plain write or read consumes a I2cStep::Write or I2cStep::Read; a longer transaction consumes steps in order. A transfer that does not match fails with ScriptError::Mismatch, which names the step and what arrived, and a test ends by checking done so an unfinished script is a failure too.

Examples

use pamoja_hal::i2c::I2c;
use pamoja_hal::script::{I2cScript, I2cStep};

// A TMP117, from its datasheet: the configuration register takes continuous conversion,
// its factory setting, and the result register counts 7.8125 millidegrees a step.
const TMP117: u8 = 0x48;
const RESULT: u8 = 0x00;
const CONFIGURATION: u8 = 0x01;
let [high, low] = 0x0220u16.to_be_bytes();
let reading = (25.0 / 0.0078125) as i16;

// The part's side: the configuration the driver must write, then 25 degrees.
let mut bus = I2cScript::new([
    I2cStep::write(TMP117, [CONFIGURATION, high, low]),
    I2cStep::write_read(TMP117, [RESULT], reading.to_be_bytes()),
]);

// The driver's side.
bus.write(TMP117, &[CONFIGURATION, high, low])?;
let mut result = [0u8; 2];
bus.write_read(TMP117, &[RESULT], &mut result)?;
assert_eq!(f64::from(i16::from_be_bytes(result)) * 0.0078125, 25.0);
assert!(bus.done(), "every transfer the part expected has happened");

Implementations

impl I2cScript

pub fn new(steps: impl IntoIterator<Item = I2cStep>) -> I2cScript

Creates a bus that expects steps in order.

Arguments

• steps - the transfers the driver is expected to make, and their replies.

Returns

The scripted bus.

pub fn done(&self) -> bool

Reports whether every step has been consumed.

Returns

true once the driver has made every transfer the script expected.

pub fn remaining(&self) -> usize

Reports how many steps remain.

Returns

The number of steps the driver has not yet reached.

pub fn consumed(&self) -> usize

Reports how many steps the driver has consumed.

Returns

The number of steps matched or faulted so far.

Trait Implementations

impl Clone for I2cScript

fn clone(&self) -> I2cScript

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for I2cScript

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

Formats the value using the given formatter.

impl Default for I2cScript

fn default() -> I2cScript

Returns the “default value” for a type.

impl ErrorType for I2cScript

type Error = ScriptError

Error type

impl I2c for I2cScript

fn transaction( &mut self, address: SevenBitAddress, operations: &mut [Operation<'_>], ) -> Result<(), ScriptError>

Execute the provided operations on the I2C bus.

fn read(&mut self, address: A, read: &mut [u8]) -> Result<(), Self::Error>

Reads enough bytes from slave with address to fill read.

fn write(&mut self, address: A, write: &[u8]) -> Result<(), Self::Error>

Writes bytes to slave with address address.

fn write_read( &mut self, address: A, write: &[u8], read: &mut [u8], ) -> Result<(), Self::Error>

Writes bytes to slave with address address and then reads enough bytes to fill read in a single transaction.