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https://github.com/italicsjenga/rp-hal-boards.git
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19e2fbea1c
* Add the Pimoroni Servo 2040 board This PR adds the board support package and two simple examples. * Animates a rainbow wheel across the RGB LEDs on the board. * Moves a servo that's connected to GPIO0 back and forth. * Format pimoroni-servo2040 board files * Use us_to_duty function in servo example, clean up comments. * Fix bad types * Add Servo2040 description to top-level readme
116 lines
3.4 KiB
Rust
116 lines
3.4 KiB
Rust
//! # Pimoroni Servo2040 PWM Micro Servo Example
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//!
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//! Moves the micro servo on a Servo2040 board using the PWM peripheral.
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//!
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//! This will move in different positions the motor attached to GP0.
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#![no_std]
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#![no_main]
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// GPIO traits
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use embedded_hal::timer::CountDown;
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use embedded_hal::PwmPin;
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// Traits for converting integers to amounts of time
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use fugit::ExtU64;
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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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// A shorter alias for the Peripheral Access Crate, which provides low-level
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// register access
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use pimoroni_servo2040::hal::pac;
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// A shorter alias for the Hardware Abstraction Layer, which provides
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// higher-level drivers.
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use pimoroni_servo2040::hal;
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/// Number of microseconds for the pwm signal period.
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const PERIOD_US: u32 = 20_000;
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/// Max resolution for the pwm signal.
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const TOP: u16 = u16::MAX;
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#[pimoroni_servo2040::entry]
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fn main() -> ! {
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let mut pac = pac::Peripherals::take().unwrap();
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let mut watchdog = hal::Watchdog::new(pac.WATCHDOG);
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let sio = hal::Sio::new(pac.SIO);
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let _clocks = hal::clocks::init_clocks_and_plls(
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pimoroni_servo2040::XOSC_CRYSTAL_FREQ,
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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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// Configure the Timer peripheral in count-down mode
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let timer = hal::Timer::new(pac.TIMER, &mut pac.RESETS);
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let mut count_down = timer.count_down();
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let pins = pimoroni_servo2040::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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let pwm_slices = hal::pwm::Slices::new(pac.PWM, &mut pac.RESETS);
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const MIN_PULSE: u16 = 1000;
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const MID_PULSE: u16 = 1500;
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const MAX_PULSE: u16 = 2000;
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let mut pwm: hal::pwm::Slice<_, _> = pwm_slices.pwm0;
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pwm.set_ph_correct();
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// 50Hz
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pwm.set_div_int(38);
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pwm.set_div_frac(3);
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pwm.set_top(TOP);
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pwm.enable();
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// Output channel A on PWM0 to the GPIO0/servo1 pin
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let mut channel_a = pwm.channel_a;
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let _channel_a_pin = channel_a.output_to(pins.servo1);
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let movement_delay = 400.millis();
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// Infinite loop, moving micro servo from one position to another.
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// You may need to adjust the pulse width since several servos from
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// different manufacturers respond differently.
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loop {
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// move to 0°
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channel_a.set_duty(us_to_duty(MID_PULSE));
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count_down.start(movement_delay);
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let _ = nb::block!(count_down.wait());
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// 0° to 90°
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channel_a.set_duty(us_to_duty(MAX_PULSE));
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count_down.start(movement_delay);
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let _ = nb::block!(count_down.wait());
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// 90° to 0°
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channel_a.set_duty(us_to_duty(MID_PULSE));
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count_down.start(movement_delay);
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let _ = nb::block!(count_down.wait());
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// 0° to -90°
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channel_a.set_duty(us_to_duty(MIN_PULSE));
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count_down.start(movement_delay);
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let _ = nb::block!(count_down.wait());
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}
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}
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/// Convert microseconds to duty value.
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///
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/// This function uses the constants TOP and PERIOD_US defined at the top of the file.
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fn us_to_duty(us: u16) -> u16 {
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// Do math in u32 so we maintain higher precision. If we do math in u16, we need to divide first
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// and lose some precision when truncating the remainder.
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(TOP as u32 * us as u32 / PERIOD_US) as u16
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}
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