db409ffe7b
* Unify the system peripheral Whilst the PCR, SYSTEM and DPORT peripherals are different, we currently use them all in the same way. This PR unifies the peripheral name in the hal to `SYSTEM`. The idea is that they all do the same sort of thing, so we can collect them under the same name, and later down the line we can being to expose differences under an extended API. The benifits to this are imo quite big, the examples now are all identical, which makes things easier for esp-wifi, and paves a path towards the multichip hal. Why not do this in the PAC? Imo the pac should be as close to the hardware as possible, and the HAL is where we should abstractions such as this. * changelog
114 lines
2.8 KiB
Rust
114 lines
2.8 KiB
Rust
//! SPI loopback test using DMA
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//!
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//! Folowing pins are used:
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//! SCLK GPIO19
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//! MISO GPIO25
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//! MOSI GPIO23
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//! CS GPIO22
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//!
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//! Depending on your target and the board you are using you have to change the
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//! pins.
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//!
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//! This example transfers data via SPI.
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//! Connect MISO and MOSI pins to see the outgoing data is read as incoming
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//! data.
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#![no_std]
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#![no_main]
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use esp32_hal::{
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clock::ClockControl,
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dma::DmaPriority,
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gpio::IO,
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pdma::Dma,
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peripherals::Peripherals,
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prelude::*,
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spi::{Spi, SpiMode},
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Delay,
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};
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use esp_backtrace as _;
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use esp_println::println;
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#[entry]
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fn main() -> ! {
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let peripherals = Peripherals::take();
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let system = peripherals.SYSTEM.split();
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let clocks = ClockControl::boot_defaults(system.clock_control).freeze();
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let io = IO::new(peripherals.GPIO, peripherals.IO_MUX);
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let sclk = io.pins.gpio19;
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let miso = io.pins.gpio25;
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let mosi = io.pins.gpio23;
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let cs = io.pins.gpio22;
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let dma = Dma::new(system.dma);
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let dma_channel = dma.spi2channel;
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let mut descriptors = [0u32; 8 * 3];
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let mut rx_descriptors = [0u32; 8 * 3];
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let mut spi = Spi::new(
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peripherals.SPI2,
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sclk,
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mosi,
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miso,
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cs,
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100u32.kHz(),
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SpiMode::Mode0,
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&clocks,
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)
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.with_dma(dma_channel.configure(
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false,
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&mut descriptors,
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&mut rx_descriptors,
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DmaPriority::Priority0,
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));
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let mut delay = Delay::new(&clocks);
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// DMA buffer require a static life-time
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let mut send = buffer1();
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let mut receive = buffer2();
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let mut i = 0;
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for (i, v) in send.iter_mut().enumerate() {
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*v = (i % 255) as u8;
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}
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loop {
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send[0] = i;
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send[send.len() - 1] = i;
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i = i.wrapping_add(1);
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let transfer = spi.dma_transfer(send, receive).unwrap();
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// here we could do something else while DMA transfer is in progress
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let mut i = 0;
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// Check is_done until the transfer is almost done (32000 bytes at 100kHz is
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// 2.56 seconds), then move to wait().
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while !transfer.is_done() && i < 10 {
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delay.delay_ms(250u32);
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i += 1;
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}
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// the buffers and spi is moved into the transfer and we can get it back via
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// `wait`
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(receive, send, spi) = transfer.wait().unwrap();
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println!(
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"{:x?} .. {:x?}",
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&receive[..10],
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&receive[receive.len() - 10..]
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);
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delay.delay_ms(250u32);
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}
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}
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fn buffer1() -> &'static mut [u8; 32000] {
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static mut BUFFER: [u8; 32000] = [0u8; 32000];
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unsafe { &mut BUFFER }
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}
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fn buffer2() -> &'static mut [u8; 32000] {
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static mut BUFFER: [u8; 32000] = [0u8; 32000];
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unsafe { &mut BUFFER }
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}
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