159 lines
4.7 KiB
Rust
159 lines
4.7 KiB
Rust
//! # PWM Blink Example
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//!
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//! If you have an LED connected to pin 25, it will fade the LED using the PWM
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//! peripheral.
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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 license details.
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#![no_std]
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#![no_main]
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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 embedded_hal::PwmPin;
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use fugit::RateExtU32;
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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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// UART related types
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use hal::uart::{DataBits, StopBits, UartConfig};
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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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/// Note: This boot block is not necessary when using a rp-hal based BSP
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/// as the BSPs already perform this step.
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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_GENERIC_03H;
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/// The minimum PWM value (i.e. LED brightness) we want
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const LOW: u16 = 0;
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/// The maximum PWM value (i.e. LED brightness) we want
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const HIGH: u16 = 25000;
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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 `#[rp2040_hal::entry]` macro ensures the Cortex-M start-up code calls this function
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/// as soon as all global variables and the spinlock are initialised.
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///
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/// The function configures the RP2040 peripherals, then fades the LED in an
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/// infinite loop.
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#[rp2040_hal::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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let core = pac::CorePeripherals::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::new(pac.WATCHDOG);
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// Configure the clocks
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//
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// The default is to generate a 125 MHz system clock
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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::new(pac.SIO);
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// Set the pins up according to their function on this particular board
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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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// The delay object lets us wait for specified amounts of time (in
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// milliseconds)
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let mut delay = cortex_m::delay::Delay::new(core.SYST, clocks.system_clock.freq().to_Hz());
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// UART
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let uart_pins = (
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// UART TX (characters sent from RP2040) on pin 1 (GPIO0)
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pins.gpio0.into_mode::<hal::gpio::FunctionUart>(),
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// UART RX (characters received by RP2040) on pin 2 (GPIO1)
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pins.gpio1.into_mode::<hal::gpio::FunctionUart>(),
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);
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let uart = hal::uart::UartPeripheral::new(pac.UART0, uart_pins, &mut pac.RESETS)
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.enable(
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UartConfig::new(9600.Hz(), DataBits::Eight, None, StopBits::One),
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clocks.peripheral_clock.freq(),
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)
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.unwrap();
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// Init PWMs
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let mut pwm_slices = hal::pwm::Slices::new(pac.PWM, &mut pac.RESETS);
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// Configure PWM4
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let pwm5 = &mut pwm_slices.pwm5;
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pwm5.set_ph_correct();
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pwm5.set_div_int(4);
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pwm5.set_div_frac((88 << 4) / 100);
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pwm5.set_top(512);
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pwm5.enable();
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let pwm6 = &mut pwm_slices.pwm6;
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pwm6.set_ph_correct();
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pwm6.enable();
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let pwm7 = &mut pwm_slices.pwm7;
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pwm7.set_ph_correct();
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pwm7.enable();
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// Output channel B on PWM4 to GPIO 25
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let channel1 = &mut pwm6.channel_b;
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channel1.output_to(pins.gpio13);
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let channel2 = &mut pwm7.channel_a;
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channel2.output_to(pins.gpio14);
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let channel3 = &mut pwm7.channel_b;
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channel3.output_to(pins.gpio15);
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let pwr_switch_ch = &mut pwm5.channel_a;
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pwr_switch_ch.output_to(pins.gpio10);
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pwr_switch_ch.set_duty(450);
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let mut ch_val: [u16; 3] = [LOW, LOW + (HIGH - LOW) / 3, LOW + 2 * (HIGH - LOW) / 3];
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uart.write_full_blocking(b"Initialization complete!\r\n");
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// Infinite loop, fading LED up and down
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loop {
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for i in 0..ch_val.len() {
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ch_val[i] += 1;
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if ch_val[i] > HIGH {
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ch_val[i] -= HIGH - LOW;
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}
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}
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channel1.set_duty(ch_val[0]);
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channel2.set_duty(ch_val[1]);
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channel3.set_duty(ch_val[2]);
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delay.delay_us(50);
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}
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}
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