mirror of
https://github.com/italicsjenga/rp-hal-boards.git
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131 lines
3.7 KiB
Rust
131 lines
3.7 KiB
Rust
//! # SPI Example
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//!
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//! This application demonstrates how to use the SPI Driver to talk to a remote
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//! SPI device.
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//!
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//!
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//! It may need to be adapted to your particular board layout and/or pin
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//! assignment.
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//!
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//! See the `Cargo.toml` file for Copyright and licence details.
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#![no_std]
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#![no_main]
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// The macro for our start-up function
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use cortex_m_rt::entry;
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// Ensure we halt the program on panic (if we don't mention this crate it won't
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// be linked)
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use panic_halt as _;
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// Alias for our HAL crate
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use rp2040_hal as hal;
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// Some traits we need
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use cortex_m::prelude::*;
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use embedded_time::rate::Extensions;
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use rp2040_hal::clocks::Clock;
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// A shorter alias for the Peripheral Access Crate, which provides low-level
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// register access
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use hal::pac;
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/// The linker will place this boot block at the start of our program image. We
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/// need this to help the ROM bootloader get our code up and running.
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#[link_section = ".boot2"]
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#[used]
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pub static BOOT2: [u8; 256] = rp2040_boot2::BOOT_LOADER_W25Q080;
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/// External high-speed crystal on the Raspberry Pi Pico board is 12 MHz. Adjust
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/// if your board has a different frequency
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const XTAL_FREQ_HZ: u32 = 12_000_000u32;
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/// Entry point to our bare-metal application.
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///
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/// The `#[entry]` macro ensures the Cortex-M start-up code calls this function
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/// as soon as all global variables are initialised.
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///
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/// The function configures the RP2040 peripherals, then performs some example
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/// SPI transactions, then goes to sleep.
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#[entry]
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fn main() -> ! {
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// Grab our singleton objects
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let mut pac = pac::Peripherals::take().unwrap();
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// Set up the watchdog driver - needed by the clock setup code
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let mut watchdog = hal::watchdog::Watchdog::new(pac.WATCHDOG);
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// Configure the clocks
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let clocks = hal::clocks::init_clocks_and_plls(
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XTAL_FREQ_HZ,
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pac.XOSC,
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pac.CLOCKS,
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pac.PLL_SYS,
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pac.PLL_USB,
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&mut pac.RESETS,
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&mut watchdog,
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)
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.ok()
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.unwrap();
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// The single-cycle I/O block controls our GPIO pins
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let sio = hal::sio::Sio::new(pac.SIO);
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// Set the pins to their default state
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let pins = hal::gpio::Pins::new(
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pac.IO_BANK0,
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pac.PADS_BANK0,
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sio.gpio_bank0,
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&mut pac.RESETS,
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);
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// These are implicitly used by the spi driver if they are in the correct mode
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let _spi_sclk = pins.gpio6.into_mode::<hal::gpio::FunctionSpi>();
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let _spi_mosi = pins.gpio7.into_mode::<hal::gpio::FunctionSpi>();
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let _spi_miso = pins.gpio4.into_mode::<hal::gpio::FunctionSpi>();
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let spi = hal::spi::Spi::<_, _, 8>::new(pac.SPI0);
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// Exchange the uninitialised SPI driver for an initialised one
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let mut spi = spi.init(
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&mut pac.RESETS,
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clocks.peripheral_clock.freq(),
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16_000_000u32.Hz(),
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&embedded_hal::spi::MODE_0,
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);
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// Write out 0, ignore return value
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if spi.write(&[0]).is_ok() {
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// SPI write was succesful
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};
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// write 50, then check the return
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let send_success = spi.send(50);
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match send_success {
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Ok(_) => {
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// We succeeded, check the read value
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if let Ok(_x) = spi.read() {
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// We got back `x` in exchange for the 0x50 we sent.
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};
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}
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Err(_) => todo!(),
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}
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// Do a read+write at the same time. Data in `buffer` will be replaced with
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// the data read from the SPI device.
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let mut buffer: [u8; 4] = [1, 2, 3, 4];
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let transfer_success = spi.transfer(&mut buffer);
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#[allow(clippy::single_match)]
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match transfer_success {
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Ok(_) => {} // Handle success
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Err(_) => {} // handle errors
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};
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#[allow(clippy::empty_loop)]
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loop {
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// Empty loop
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}
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}
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// End of file
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