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nrf: docs.

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This commit is contained in:
Dario Nieuwenhuis
2023-02-01 00:48:33 +01:00
parent ca10fe7135
commit b5cf332cc0
40 changed files with 694 additions and 245 deletions
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73
embassy-nrf/src/twim.rs
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@ -1,11 +1,7 @@
//! I2C-compatible Two Wire Interface in master mode (TWIM) driver.
#![macro_use]
//! HAL interface to the TWIM peripheral.
//!
//! See product specification:
//!
//! - nRF52832: Section 33
//! - nRF52840: Section 6.31
use core::future::{poll_fn, Future};
use core::sync::atomic::compiler_fence;
use core::sync::atomic::Ordering::SeqCst;
@ -23,22 +19,39 @@ use crate::interrupt::{Interrupt, InterruptExt};
use crate::util::{slice_in_ram, slice_in_ram_or};
use crate::{gpio, pac, Peripheral};
/// TWI frequency
#[derive(Clone, Copy)]
pub enum Frequency {
#[doc = "26738688: 100 kbps"]
/// 100 kbps
K100 = 26738688,
#[doc = "67108864: 250 kbps"]
/// 250 kbps
K250 = 67108864,
#[doc = "104857600: 400 kbps"]
/// 400 kbps
K400 = 104857600,
}
/// TWIM config.
#[non_exhaustive]
pub struct Config {
/// Frequency
pub frequency: Frequency,
/// Enable high drive for the SDA line.
pub sda_high_drive: bool,
/// Enable internal pullup for the SDA line.
///
/// Note that using external pullups is recommended for I2C, and
/// most boards already have them.
pub sda_pullup: bool,
/// Enable high drive for the SCL line.
pub scl_high_drive: bool,
/// Enable internal pullup for the SCL line.
///
/// Note that using external pullups is recommended for I2C, and
/// most boards already have them.
pub scl_pullup: bool,
}
@ -54,29 +67,38 @@ impl Default for Config {
}
}
/// TWI error.
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
#[non_exhaustive]
pub enum Error {
/// TX buffer was too long.
TxBufferTooLong,
/// RX buffer was too long.
RxBufferTooLong,
/// Data transmit failed.
Transmit,
/// Data reception failed.
Receive,
DMABufferNotInDataMemory,
/// The buffer is not in data RAM. It's most likely in flash, and nRF's DMA cannot access flash.
BufferNotInRAM,
/// Didn't receive an ACK bit after the address byte. Address might be wrong, or the i2c device chip might not be connected properly.
AddressNack,
/// Didn't receive an ACK bit after a data byte.
DataNack,
/// Overrun error.
Overrun,
/// Timeout error.
Timeout,
}
/// Interface to a TWIM instance using EasyDMA to offload the transmission and reception workload.
///
/// For more details about EasyDMA, consult the module documentation.
/// TWI driver.
pub struct Twim<'d, T: Instance> {
_p: PeripheralRef<'d, T>,
}
impl<'d, T: Instance> Twim<'d, T> {
/// Create a new TWI driver.
pub fn new(
twim: impl Peripheral<P = T> + 'd,
irq: impl Peripheral<P = T::Interrupt> + 'd,
@ -153,7 +175,7 @@ impl<'d, T: Instance> Twim<'d, T> {
/// Set TX buffer, checking that it is in RAM and has suitable length.
unsafe fn set_tx_buffer(&mut self, buffer: &[u8]) -> Result<(), Error> {
slice_in_ram_or(buffer, Error::DMABufferNotInDataMemory)?;
slice_in_ram_or(buffer, Error::BufferNotInRAM)?;
if buffer.len() > EASY_DMA_SIZE {
return Err(Error::TxBufferTooLong);
@ -233,7 +255,7 @@ impl<'d, T: Instance> Twim<'d, T> {
return Err(Error::DataNack);
}
if err.overrun().is_received() {
return Err(Error::DataNack);
return Err(Error::Overrun);
}
Ok(())
}
@ -435,7 +457,7 @@ impl<'d, T: Instance> Twim<'d, T> {
) -> Result<(), Error> {
match self.setup_write_read_from_ram(address, wr_buffer, rd_buffer, inten) {
Ok(_) => Ok(()),
Err(Error::DMABufferNotInDataMemory) => {
Err(Error::BufferNotInRAM) => {
trace!("Copying TWIM tx buffer into RAM for DMA");
let tx_ram_buf = &mut [0; FORCE_COPY_BUFFER_SIZE][..wr_buffer.len()];
tx_ram_buf.copy_from_slice(wr_buffer);
@ -448,7 +470,7 @@ impl<'d, T: Instance> Twim<'d, T> {
fn setup_write(&mut self, address: u8, wr_buffer: &[u8], inten: bool) -> Result<(), Error> {
match self.setup_write_from_ram(address, wr_buffer, inten) {
Ok(_) => Ok(()),
Err(Error::DMABufferNotInDataMemory) => {
Err(Error::BufferNotInRAM) => {
trace!("Copying TWIM tx buffer into RAM for DMA");
let tx_ram_buf = &mut [0; FORCE_COPY_BUFFER_SIZE][..wr_buffer.len()];
tx_ram_buf.copy_from_slice(wr_buffer);
@ -612,6 +634,10 @@ impl<'d, T: Instance> Twim<'d, T> {
// ===========================================
/// Read from an I2C slave.
///
/// The buffer must have a length of at most 255 bytes on the nRF52832
/// and at most 65535 bytes on the nRF52840.
pub async fn read(&mut self, address: u8, buffer: &mut [u8]) -> Result<(), Error> {
self.setup_read(address, buffer, true)?;
self.async_wait().await;
@ -621,6 +647,10 @@ impl<'d, T: Instance> Twim<'d, T> {
Ok(())
}
/// Write to an I2C slave.
///
/// The buffer must have a length of at most 255 bytes on the nRF52832
/// and at most 65535 bytes on the nRF52840.
pub async fn write(&mut self, address: u8, buffer: &[u8]) -> Result<(), Error> {
self.setup_write(address, buffer, true)?;
self.async_wait().await;
@ -640,6 +670,11 @@ impl<'d, T: Instance> Twim<'d, T> {
Ok(())
}
/// Write data to an I2C slave, then read data from the slave without
/// triggering a stop condition between the two.
///
/// The buffers must have a length of at most 255 bytes on the nRF52832
/// and at most 65535 bytes on the nRF52840.
pub async fn write_read(&mut self, address: u8, wr_buffer: &[u8], rd_buffer: &mut [u8]) -> Result<(), Error> {
self.setup_write_read(address, wr_buffer, rd_buffer, true)?;
self.async_wait().await;
@ -705,7 +740,9 @@ pub(crate) mod sealed {
}
}
/// TWIM peripheral instance.
pub trait Instance: Peripheral<P = Self> + sealed::Instance + 'static {
/// Interrupt for this peripheral.
type Interrupt: Interrupt;
}
@ -776,7 +813,7 @@ mod eh1 {
Self::RxBufferTooLong => embedded_hal_1::i2c::ErrorKind::Other,
Self::Transmit => embedded_hal_1::i2c::ErrorKind::Other,
Self::Receive => embedded_hal_1::i2c::ErrorKind::Other,
Self::DMABufferNotInDataMemory => embedded_hal_1::i2c::ErrorKind::Other,
Self::BufferNotInRAM => embedded_hal_1::i2c::ErrorKind::Other,
Self::AddressNack => {
embedded_hal_1::i2c::ErrorKind::NoAcknowledge(embedded_hal_1::i2c::NoAcknowledgeSource::Address)
}