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| //! # gpin External Clocks example | ||
| //! | ||
| //! This application demonstrates how to clock the processor using an external clock on GPIO20 | ||
| //! | ||
| //! It may need to be adapted to your particular board layout and/or pin assignment. | ||
| //! | ||
| //! See the top-level `README.md` file for Copyright and license details. | ||
| #![no_std] | ||
| #![no_main] | ||
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| use embedded_hal_0_2::digital::v2::ToggleableOutputPin; | ||
| // Ensure we halt the program on panic (if we don't mention this crate it won't | ||
| // be linked) | ||
| use panic_halt as _; | ||
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| // To use the .MHz() function | ||
| use fugit::RateExtU32; | ||
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| use rp2040_hal::clocks::ClockSource; | ||
| // Alias for our HAL crate | ||
| use rp2040_hal as hal; | ||
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| // Necessary HAL types | ||
| use hal::{clocks::ClocksManager, gpin::GpIn0, gpio, Clock, Sio}; | ||
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| // A shorter alias for the Peripheral Access Crate, which provides low-level | ||
| // register access | ||
| use hal::pac; | ||
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| /// The linker will place this boot block at the start of our program image. We | ||
| /// need this to help the ROM bootloader get our code up and running. | ||
| /// Note: This boot block is not necessary when using a rp-hal based BSP | ||
| /// as the BSPs already perform this step. | ||
| #[link_section = ".boot2"] | ||
| #[used] | ||
| pub static BOOT2: [u8; 256] = rp2040_boot2::BOOT_LOADER_GENERIC_03H; | ||
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| // The external clock provided to GPIO pin 20. | ||
| const GPIN_EXTERNAL_CLOCK_FREQ_HZ: u32 = 1_000_000u32; | ||
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| /// Entry point to our bare-metal application. | ||
| /// | ||
| /// The `#[rp2040_hal::entry]` macro ensures the Cortex-M start-up code calls this function | ||
| /// as soon as all global variables and the spinlock are initialised. | ||
| /// | ||
| /// The function configures the RP2040 to accept an external clock on Gpio20, | ||
| /// then configures the system clock to run off this clock. | ||
| #[rp2040_hal::entry] | ||
| fn main() -> ! { | ||
| let mut pac = pac::Peripherals::take().unwrap(); | ||
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| let sio = Sio::new(pac.SIO); | ||
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| let pins = gpio::Pins::new( | ||
| pac.IO_BANK0, | ||
| pac.PADS_BANK0, | ||
| sio.gpio_bank0, | ||
| &mut pac.RESETS, | ||
| ); | ||
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| let gpin0_pin = pins.gpio20.reconfigure(); | ||
| let gpin0: GpIn0 = GpIn0::new(gpin0_pin, GPIN_EXTERNAL_CLOCK_FREQ_HZ.Hz()); | ||
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| let mut clocks = ClocksManager::new(pac.CLOCKS); | ||
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| clocks | ||
| .system_clock | ||
| .configure_clock(&gpin0, gpin0.get_freq()) | ||
| .unwrap(); | ||
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| let mut test_pin = pins.gpio0.into_push_pull_output(); | ||
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| loop { | ||
| // Continuously toggle a pin so it's possible to observe on a scope that the pico runs on | ||
| // the externally provided frequency, and is synchronized to it. | ||
| test_pin.toggle().unwrap(); | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,56 @@ | ||
| //! Defines a wrapper for the GPIO pins that can route external clocks into the RP2040. | ||
| //! | ||
| //! See [2.15.2.3. External Clocks](https://datasheets.raspberrypi.org/rp2040/rp2040-datasheet.pdf) for more details. | ||
| //! Or see [examples/gpin.rs](https://github.com/rp-rs/rp-hal/tree/main/rp2040-hal-examples/src/bin/gpin.rs) for a practical example | ||
| use fugit::HertzU32; | ||
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| use crate::{ | ||
| gpio::{ | ||
| bank0::{Gpio20, Gpio22}, | ||
| FunctionClock, Pin, PullNone, PullType, | ||
| }, | ||
| typelevel::Sealed, | ||
| }; | ||
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| macro_rules! gpin { | ||
| ($id:ident, $pin:ident) => { | ||
| /// A gpin pin: a pin that can be used as a clock input. | ||
| pub struct $id<M = PullNone> | ||
| where | ||
| M: PullType, | ||
| { | ||
| pin: Pin<$pin, FunctionClock, M>, | ||
| frequency: HertzU32, | ||
| } | ||
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| impl<M: PullType> $id<M> { | ||
| #[doc = concat!("Creates a new ", stringify!($id), " given the input pin.")] | ||
| pub fn new(pin: Pin<$pin, FunctionClock, M>, frequency: HertzU32) -> Self { | ||
| Self { pin, frequency } | ||
| } | ||
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| /// Set the frequency of the externally applied clock signal. | ||
| /// This frequency is used when computing clock dividers. | ||
| pub fn set_frequency(mut self, frequency: HertzU32) -> Self { | ||
| self.frequency = frequency; | ||
| self | ||
| } | ||
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| /// Retrieve frequency | ||
| pub fn frequency(&self) -> HertzU32 { | ||
| self.frequency | ||
| } | ||
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| #[doc = concat!("Release the underlying device and ", stringify!($pin), ".")] | ||
| pub fn free(self) -> Pin<$pin, FunctionClock, M> { | ||
| self.pin | ||
| } | ||
| } | ||
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| impl<M: PullType> Sealed for $id<M> {} | ||
| }; | ||
| } | ||
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| gpin!(GpIn0, Gpio20); | ||
| gpin!(GpIn1, Gpio22); |
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