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Adding updated docs for adc file

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This commit is contained in:
Ryan Summers 2020-11-11 11:57:14 +01:00
parent 9cfb52308d
commit aa36446f95
4 changed files with 156 additions and 31 deletions
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2
Cargo.lock generated
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@ -501,7 +501,7 @@ dependencies = [
[[package]]
name = "stm32h7xx-hal"
version = "0.8.0"
source = "git+https://github.com/quartiq/stm32h7xx-hal?branch=feature/stabilizer-dma#5fbbfa9352f720994c210e5c21601f3acf9dc40c"
source = "git+https://github.com/quartiq/stm32h7xx-hal?branch=feature/dma-rtic-example#d8cb6fa5099282665f5e5068a9dcdc9ebaa63240"
dependencies = [
"bare-metal 1.0.0",
"cast",

4
Cargo.toml
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@ -55,7 +55,7 @@ path = "ad9959"
[dependencies.stm32h7xx-hal]
features = ["stm32h743v", "rt", "unproven", "ethernet", "quadspi"]
git = "https://github.com/quartiq/stm32h7xx-hal"
branch = "feature/stabilizer-dma"
branch = "feature/dma-rtic-example"
[features]
semihosting = ["panic-semihosting", "cortex-m-log/semihosting"]
@ -65,7 +65,7 @@ nightly = ["cortex-m/inline-asm"]
[profile.dev]
codegen-units = 1
incremental = false
opt-level = 1
opt-level = 3
[profile.release]
opt-level = 3

169
src/adc.rs
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@ -1,13 +1,36 @@
///! Stabilizer ADC management interface
///!
///! The Stabilizer ADCs utilize a DMA channel to trigger sampling. The SPI streams are configured
///! for full-duplex operation, but only RX is connected to physical pins. A timer channel is
///! configured to generate a DMA write into the SPI TXFIFO, which initiates a SPI transfer and
///! results in an ADC sample read for both channels.
///!
///! In order to read multiple samples without interrupting the CPU, a separate DMA transfer is
///! configured to read from each of the ADC SPI RX FIFOs. Due to the design of the SPI peripheral,
///! these DMA transfers stall when no data is available in the FIFO. Thus, the DMA transfer only
///! completes after all samples have been read. When this occurs, a CPU interrupt is generated so
///! that software can process the acquired samples from both ADCs. Only one of the ADC DMA streams
///! is configured to generate an interrupt to handle both transfers, so it is necessary to ensure
///! both transfers are completed before reading the data. This is usually not significant for
///! busy-waiting because the transfers should complete at approximately the same time.
use super::{
hal, DMAReq, DmaConfig, MemoryToPeripheral, PeripheralToMemory, Priority,
Stream, TargetAddress, Transfer,
hal, DMAReq, DmaConfig, MemoryToPeripheral, PeripheralToMemory, Priority, TargetAddress,
Transfer,
};
// The desired ADC input buffer size. This is use configurable.
const INPUT_BUFFER_SIZE: usize = 1;
// The following data is written by the timer ADC sample trigger into each of the SPI TXFIFOs. Note
// that because the SPI MOSI line is not connected, this data is dont-care. Data in AXI SRAM is not
// initialized on boot, so the contents are random.
#[link_section = ".axisram.buffers"]
static mut SPI_START: [u16; 1] = [0x00];
// The following global buffers are used for the ADC sample DMA transfers. Two buffers are used for
// each transfer in a ping-pong buffer configuration (one is being acquired while the other is being
// processed). Note that the contents of AXI SRAM is uninitialized, so the buffer contents on
// startup are undefined.
#[link_section = ".axisram.buffers"]
static mut ADC0_BUF0: [u16; INPUT_BUFFER_SIZE] = [0; INPUT_BUFFER_SIZE];
@ -20,8 +43,9 @@ static mut ADC1_BUF0: [u16; INPUT_BUFFER_SIZE] = [0; INPUT_BUFFER_SIZE];
#[link_section = ".axisram.buffers"]
static mut ADC1_BUF1: [u16; INPUT_BUFFER_SIZE] = [0; INPUT_BUFFER_SIZE];
/// SPI2 is used as a ZST (zero-sized type) for indicating a DMA transfer into the SPI2 TX FIFO
/// whenever the tim2 update dma request occurs.
struct SPI2 {}
impl SPI2 {
pub fn new() -> Self {
Self {}
@ -29,18 +53,23 @@ impl SPI2 {
}
unsafe impl TargetAddress<MemoryToPeripheral> for SPI2 {
/// SPI2 is configured to operate using 16-bit transfer words.
type MemSize = u16;
const REQUEST_LINE: Option<u8> = Some(DMAReq::TIM2_UP as u8);
/// SPI2 DMA requests are generated whenever TIM2 CH1 comparison occurs.
const REQUEST_LINE: Option<u8> = Some(DMAReq::TIM2_CH1 as u8);
/// Whenever the DMA request occurs, it should write into SPI2's TX FIFO to start a DMA
/// transfer.
fn address(&self) -> u32 {
let regs = unsafe { &*hal::stm32::SPI2::ptr() };
&regs.txdr as *const _ as u32
}
}
/// SPI3 is used as a ZST (zero-sized type) for indicating a DMA transfer into the SPI3 TX FIFO
/// whenever the tim2 update dma request occurs.
struct SPI3 {}
impl SPI3 {
pub fn new() -> Self {
Self {}
@ -48,26 +77,37 @@ impl SPI3 {
}
unsafe impl TargetAddress<MemoryToPeripheral> for SPI3 {
/// SPI3 is configured to operate using 16-bit transfer words.
type MemSize = u16;
const REQUEST_LINE: Option<u8> = Some(DMAReq::TIM2_UP as u8);
/// SPI3 DMA requests are generated whenever TIM2 CH2 comparison occurs.
const REQUEST_LINE: Option<u8> = Some(DMAReq::TIM2_CH2 as u8);
/// Whenever the DMA request occurs, it should write into SPI3's TX FIFO to start a DMA
/// transfer.
fn address(&self) -> u32 {
let regs = unsafe { &*hal::stm32::SPI3::ptr() };
&regs.txdr as *const _ as u32
}
}
/// Represents both ADC input channels.
pub struct AdcInputs {
adc0: Adc0Input,
adc1: Adc1Input,
}
impl AdcInputs {
/// Construct the ADC inputs.
pub fn new(adc0: Adc0Input, adc1: Adc1Input) -> Self {
Self { adc0, adc1 }
}
/// Interrupt handler to handle when the sample collection DMA transfer completes.
///
/// # Returns
/// (adc0, adc1) where adcN is a reference to the collected ADC samples. Two array references
/// are returned - one for each ADC sample stream.
pub fn transfer_complete_handler(
&mut self,
) -> (&[u16; INPUT_BUFFER_SIZE], &[u16; INPUT_BUFFER_SIZE]) {
@ -77,6 +117,7 @@ impl AdcInputs {
}
}
/// Represents data associated with ADC0.
pub struct Adc0Input {
next_buffer: Option<&'static mut [u16; INPUT_BUFFER_SIZE]>,
transfer: Transfer<
@ -85,72 +126,113 @@ pub struct Adc0Input {
PeripheralToMemory,
&'static mut [u16; INPUT_BUFFER_SIZE],
>,
_trigger_transfer: Transfer<
hal::dma::dma::Stream0<hal::stm32::DMA1>,
SPI2,
MemoryToPeripheral,
&'static mut [u16; 1],
>,
}
impl Adc0Input {
/// Construct the ADC0 input channel.
///
/// # Args
/// * `spi` - The SPI interface used to communicate with the ADC.
/// * `trigger_stream` - The DMA stream used to trigger each ADC transfer by writing a word into
/// the SPI TX FIFO.
/// * `data_stream` - The DMA stream used to read samples received over SPI into a data buffer.
pub fn new(
spi: hal::spi::Spi<hal::stm32::SPI2, hal::spi::Enabled, u16>,
trigger_stream: hal::dma::dma::Stream0<hal::stm32::DMA1>,
data_stream: hal::dma::dma::Stream1<hal::stm32::DMA1>,
) -> Self {
// The trigger stream constantly writes to the TX FIFO using a static word (dont-care
// contents). Thus, neither the memory or peripheral address ever change. This is run in
// circular mode to be completed at every DMA request.
let trigger_config = DmaConfig::default()
.memory_increment(false)
.peripheral_increment(false)
.priority(Priority::High)
.circular_buffer(true);
// Construct the trigger stream to write from memory to the peripheral.
let mut trigger_transfer: Transfer<_, _, MemoryToPeripheral, _> =
Transfer::init(
trigger_stream,
&SPI2::new(),
SPI2::new(),
unsafe { &mut SPI_START },
None,
trigger_config,
);
// The data stream constantly reads from the SPI RX FIFO into a RAM buffer. The peripheral
// stalls reads of the SPI RX FIFO until data is available, so the DMA transfer completes
// after the requested number of samples have been collected. Note that only ADC1's data
// stream is used to trigger a transfer completion interrupt.
let data_config = DmaConfig::default()
.memory_increment(true)
.priority(Priority::VeryHigh)
.peripheral_increment(false);
// A SPI peripheral error interrupt is used to determine if the RX FIFO overflows. This
// indicates that samples were dropped due to excessive processing time in the main
// application (e.g. a second DMA transfer completes before the first was done with
// processing). This is used as a flow control indicator to guarantee that no ADC samples
// are lost.
let mut spi = spi.disable();
spi.listen(hal::spi::Event::Error);
// The data transfer is always a transfer of data from the peripheral to a RAM buffer.
let mut data_transfer: Transfer<_, _, PeripheralToMemory, _> =
Transfer::init(
data_stream,
&spi,
spi,
unsafe { &mut ADC0_BUF0 },
None,
data_config,
);
spi.enable_dma_rx();
spi.enable_dma_tx();
data_transfer.start(|spi| {
// Allow the SPI FIFOs to operate using only DMA data channels.
spi.enable_dma_rx();
spi.enable_dma_tx();
let spi = spi.enable();
spi.inner().cr1.modify(|_, w| w.cstart().started());
// Enable SPI and start it in infinite transaction mode.
spi.inner().cr1.modify(|_, w| w.spe().set_bit());
spi.inner().cr1.modify(|_, w| w.cstart().started());
});
data_transfer.start();
trigger_transfer.start();
trigger_transfer.start(|_| {});
Self {
next_buffer: unsafe { Some(&mut ADC0_BUF1) },
transfer: data_transfer,
_trigger_transfer: trigger_transfer,
}
}
/// Handle a transfer completion.
///
/// # Returns
/// A reference to the underlying buffer that has been filled with ADC samples.
pub fn transfer_complete_handler(&mut self) -> &[u16; INPUT_BUFFER_SIZE] {
let next_buffer = self.next_buffer.take().unwrap();
while hal::dma::dma::Stream1::<hal::stm32::DMA1>::is_enabled() {}
// Wait for the transfer to fully complete before continuing.
while self.transfer.get_transfer_complete_flag() == false {}
// Start the next transfer.
self.transfer.clear_interrupts();
let (prev_buffer, _) =
self.transfer.next_transfer(next_buffer).unwrap();
self.next_buffer.replace(prev_buffer);
self.next_buffer.as_ref().unwrap()
}
}
/// Represents the data input stream from ADC1
pub struct Adc1Input {
next_buffer: Option<&'static mut [u16; INPUT_BUFFER_SIZE]>,
transfer: Transfer<
@ -159,68 +241,107 @@ pub struct Adc1Input {
PeripheralToMemory,
&'static mut [u16; INPUT_BUFFER_SIZE],
>,
_trigger_transfer: Transfer<
hal::dma::dma::Stream2<hal::stm32::DMA1>,
SPI3,
MemoryToPeripheral,
&'static mut [u16; 1],
>,
}
impl Adc1Input {
/// Construct a new ADC1 input data stream.
///
/// # Args
/// * `spi` - The SPI interface connected to ADC1.
/// * `trigger_stream` - The DMA stream used to trigger ADC conversions on the SPI interface.
/// * `data_stream` - The DMA stream used to read ADC samples from the SPI RX FIFO.
pub fn new(
spi: hal::spi::Spi<hal::stm32::SPI3, hal::spi::Enabled, u16>,
trigger_stream: hal::dma::dma::Stream2<hal::stm32::DMA1>,
data_stream: hal::dma::dma::Stream3<hal::stm32::DMA1>,
) -> Self {
// The trigger stream constantly writes to the TX FIFO using a static word (dont-care
// contents). Thus, neither the memory or peripheral address ever change. This is run in
// circular mode to be completed at every DMA request.
let trigger_config = DmaConfig::default()
.memory_increment(false)
.peripheral_increment(false)
.priority(Priority::High)
.circular_buffer(true);
// Construct the trigger stream to write from memory to the peripheral.
let mut trigger_transfer: Transfer<_, _, MemoryToPeripheral, _> =
Transfer::init(
trigger_stream,
&SPI3::new(),
SPI3::new(),
unsafe { &mut SPI_START },
None,
trigger_config,
);
// The data stream constantly reads from the SPI RX FIFO into a RAM buffer. The peripheral
// stalls reads of the SPI RX FIFO until data is available, so the DMA transfer completes
// after the requested number of samples have been collected. Note that only ADC1's data
// stream is used to trigger a transfer completion interrupt.
let data_config = DmaConfig::default()
.memory_increment(true)
.transfer_complete_interrupt(true)
.priority(Priority::VeryHigh)
.peripheral_increment(false);
// A SPI peripheral error interrupt is used to determine if the RX FIFO overflows. This
// indicates that samples were dropped due to excessive processing time in the main
// application (e.g. a second DMA transfer completes before the first was done with
// processing). This is used as a flow control indicator to guarantee that no ADC samples
// are lost.
let mut spi = spi.disable();
spi.listen(hal::spi::Event::Error);
// The data transfer is always a transfer of data from the peripheral to a RAM buffer.
let mut data_transfer: Transfer<_, _, PeripheralToMemory, _> =
Transfer::init(
data_stream,
&spi,
spi,
unsafe { &mut ADC1_BUF0 },
None,
data_config,
);
spi.enable_dma_rx();
spi.enable_dma_tx();
data_transfer.start(|spi| {
// Allow the SPI FIFOs to operate using only DMA data channels.
spi.enable_dma_rx();
spi.enable_dma_tx();
let spi = spi.enable();
spi.inner().cr1.modify(|_, w| w.cstart().started());
// Enable SPI and start it in infinite transaction mode.
spi.inner().cr1.modify(|_, w| w.spe().set_bit());
spi.inner().cr1.modify(|_, w| w.cstart().started());
});
data_transfer.start();
trigger_transfer.start();
trigger_transfer.start(|_| {});
Self {
next_buffer: unsafe { Some(&mut ADC1_BUF1) },
transfer: data_transfer,
_trigger_transfer: trigger_transfer,
}
}
/// Handle a transfer completion.
///
/// # Returns
/// A reference to the underlying buffer that has been filled with ADC samples.
pub fn transfer_complete_handler(&mut self) -> &[u16; INPUT_BUFFER_SIZE] {
let next_buffer = self.next_buffer.take().unwrap();
while hal::dma::dma::Stream3::<hal::stm32::DMA1>::is_enabled() {}
// Wait for the transfer to fully complete before continuing.
while self.transfer.get_transfer_complete_flag() == false {}
// Start the next transfer.
self.transfer.clear_interrupts();
let (prev_buffer, _) =
self.transfer.next_transfer(next_buffer).unwrap();
self.next_buffer.replace(prev_buffer);
self.next_buffer.as_ref().unwrap()
}

12
src/main.rs
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@ -1,6 +1,4 @@
#![deny(warnings)]
// Deprecation warnings are temporarily allowed as the HAL DMA goes through updates.
#![allow(deprecated)]
#![allow(clippy::missing_safety_doc)]
#![no_std]
#![no_main]
@ -41,7 +39,7 @@ use hal::{
dma::{
config::Priority,
dma::{DMAReq, DmaConfig},
traits::{Stream, TargetAddress},
traits::TargetAddress,
MemoryToPeripheral, PeripheralToMemory, Transfer,
},
ethernet::{self, PHY},
@ -706,8 +704,14 @@ const APP: () = {
&ccdr.clocks,
);
{
// Listen to the CH1 and CH2 comparison events. These channels should have a value of
// zero loaded into them, so the event should occur whenever the timer overflows. Note
// that we use channels instead of timer updates because each SPI DMA transfer needs a
// unique request line.
let t2_regs = unsafe { &*hal::stm32::TIM2::ptr() };
t2_regs.dier.modify(|_, w| w.ude().set_bit());
t2_regs
.dier
.modify(|_, w| w.cc1de().set_bit().cc2de().set_bit());
}
init::LateResources {