#![allow(clippy::inconsistent_digit_grouping, clippy::unusual_byte_groupings)]
use core::fmt;
use embedded_hal::blocking::spi::{Transfer, Write};
use crate::bus::Bus;
const WRITE_MODE_MASK: u8 = 0b00000_1_0;
const FIXED_DATA_LENGTH_MODE_1: u8 = 0b000000_01;
const FIXED_DATA_LENGTH_MODE_2: u8 = 0b000000_10;
const FIXED_DATA_LENGTH_MODE_4: u8 = 0b000000_11;
pub struct ThreeWire<Spi: Transfer<u8> + Write<u8>> {
spi: Spi,
}
impl<Spi: Transfer<u8> + Write<u8>> ThreeWire<Spi> {
pub fn new(spi: Spi) -> Self {
Self { spi }
}
pub fn release(self) -> Spi {
self.spi
}
}
impl<Spi: Transfer<u8> + Write<u8>> Bus for ThreeWire<Spi> {
type Error = ThreeWireError<<Spi as Transfer<u8>>::Error, <Spi as Write<u8>>::Error>;
fn read_frame(
&mut self,
block: u8,
mut address: u16,
data: &mut [u8],
) -> Result<(), Self::Error> {
let mut control_phase = block << 3;
let mut data_phase = data;
let mut last_length_written: u16;
while !data_phase.is_empty() {
if data_phase.len() >= 4 {
control_phase |= FIXED_DATA_LENGTH_MODE_4;
last_length_written = 4;
} else if data_phase.len() >= 2 {
control_phase |= FIXED_DATA_LENGTH_MODE_2;
last_length_written = 2;
} else {
control_phase |= FIXED_DATA_LENGTH_MODE_1;
last_length_written = 1;
}
let address_phase = address.to_be_bytes();
self.spi
.write(&address_phase)
.and_then(|_| self.spi.write(&[control_phase]))
.map_err(ThreeWireError::WriteError)?;
self.spi
.transfer(&mut data_phase[..last_length_written as usize])
.map_err(ThreeWireError::TransferError)?;
address += last_length_written;
data_phase = &mut data_phase[last_length_written as usize..];
}
Ok(())
}
fn write_frame(&mut self, block: u8, mut address: u16, data: &[u8]) -> Result<(), Self::Error> {
let mut control_phase = block << 3 | WRITE_MODE_MASK;
let mut data_phase = data;
let mut last_length_written: u16;
while !data_phase.is_empty() {
if data_phase.len() >= 4 {
control_phase |= FIXED_DATA_LENGTH_MODE_4;
last_length_written = 4;
} else if data_phase.len() >= 2 {
control_phase |= FIXED_DATA_LENGTH_MODE_2;
last_length_written = 2;
} else {
control_phase |= FIXED_DATA_LENGTH_MODE_1;
last_length_written = 1;
}
let address_phase = address.to_be_bytes();
self.spi
.write(&address_phase)
.and_then(|_| self.spi.write(&[control_phase]))
.and_then(|_| self.spi.write(&data_phase[..last_length_written as usize]))
.map_err(ThreeWireError::WriteError)?;
address += last_length_written;
data_phase = &data_phase[last_length_written as usize..];
}
Ok(())
}
}
pub enum ThreeWireError<TransferError, WriteError> {
TransferError(TransferError),
WriteError(WriteError),
}
impl<TransferError, WriteError> fmt::Debug for ThreeWireError<TransferError, WriteError> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(
f,
"ThreeWireError::{}",
match self {
Self::TransferError(_) => "TransferError",
Self::WriteError(_) => "WriteError",
}
)
}
}