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- #![no_std]
- #![no_main]
- /**
- Transmits data over an SPI port using DMA
- */
- use panic_halt as _;
- use cortex_m_rt::entry;
- use stm32f1xx_hal::{
- pac,
- prelude::*,
- spi::{Mode, Phase, Polarity, Spi},
- };
- #[entry]
- fn main() -> ! {
- // Get access to the device specific peripherals from the peripheral access crate
- let dp = pac::Peripherals::take().unwrap();
- // Take ownership over the raw flash and rcc devices and convert them into the corresponding
- // HAL structs
- let mut flash = dp.FLASH.constrain();
- let mut rcc = dp.RCC.constrain();
- // Freeze the configuration of all the clocks in the system and store the frozen frequencies in
- // `clocks`
- let clocks = rcc.cfgr.freeze(&mut flash.acr);
- // Acquire the GPIOB peripheral
- let mut gpiob = dp.GPIOB.split(&mut rcc.apb2);
- let pins = (
- gpiob.pb13.into_alternate_push_pull(&mut gpiob.crh),
- gpiob.pb14.into_floating_input(&mut gpiob.crh),
- gpiob.pb15.into_alternate_push_pull(&mut gpiob.crh),
- );
- let spi_mode = Mode {
- polarity: Polarity::IdleLow,
- phase: Phase::CaptureOnFirstTransition,
- };
- let spi = Spi::spi2(dp.SPI2, pins, spi_mode, 100.khz(), clocks, &mut rcc.apb1);
- // Set up the DMA device
- let dma = dp.DMA1.split(&mut rcc.ahb);
- // Connect the SPI device to the DMA
- let spi_dma = spi.with_tx_dma(dma.5);
- // Start a DMA transfer
- let transfer = spi_dma.write(b"hello, world");
- // Wait for it to finnish. The transfer takes ownership over the SPI device
- // and the data being sent anb those things are returned by transfer.wait
- let (_buffer, _spi_dma) = transfer.wait();
- loop {}
- }
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