mirror of
https://github.com/italicsjenga/rp-hal-boards.git
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107 lines
3.1 KiB
Rust
107 lines
3.1 KiB
Rust
//! # I²C Example
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//!
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//! This application demonstrates how to talk to I²C devices with an RP2040.
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//!
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//! It may need to be adapted to your particular board layout and/or pin 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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// Some traits we need
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use embedded_hal::blocking::i2c::Write;
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use embedded_time::rate::Extensions;
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// Alias for our HAL crate
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use rp2040_hal as hal;
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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 a single I²C
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/// write to a fixed address.
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#[entry]
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fn main() -> ! {
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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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// Configure two pins as being I²C, not GPIO
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let sda_pin = pins.gpio18.into_mode::<hal::gpio::FunctionI2C>();
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let scl_pin = pins.gpio19.into_mode::<hal::gpio::FunctionI2C>();
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// let not_an_scl_pin = pins.gpio20.into_mode::<hal::gpio::FunctionI2C>();
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// Create the I²C drive, using the two pre-configured pins. This will fail
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// at compile time if the pins are in the wrong mode, or if this I²C
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// peripheral isn't available on these pins!
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let mut i2c = hal::i2c::I2C::i2c1(
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pac.I2C1,
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sda_pin,
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scl_pin, // Try `not_an_scl_pin` here
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400.kHz(),
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&mut pac.RESETS,
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clocks.peripheral_clock,
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);
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// Write three bytes to the I²C device with 7-bit address 0x2C
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i2c.write(0x2c, &[1, 2, 3]).unwrap();
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// Demo finish - just loop until reset
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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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