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Better docs and adding of release for PioPwm

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This commit is contained in:
Bjorn 2024-10-09 10:12:43 -07:00
parent e47c031b67
commit 22fe493257
1 changed files with 14 additions and 5 deletions
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19
embassy-rp/src/pio_programs/pwm.rs
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@ -1,6 +1,7 @@
//! PIO backed PWM driver //! PIO backed PWM driver
use core::time::Duration; use core::time::Duration;
use crate::pio::Pin;
use pio::InstructionOperands; use pio::InstructionOperands;
@ -8,6 +9,7 @@ use crate::clocks;
use crate::gpio::Level; use crate::gpio::Level;
use crate::pio::{Common, Config, Direction, Instance, LoadedProgram, PioPin, StateMachine}; use crate::pio::{Common, Config, Direction, Instance, LoadedProgram, PioPin, StateMachine};
/// This converts the duration provided into the number of cycles the PIO needs to run to make it take the same time
fn to_pio_cycles(duration: Duration) -> u32 { fn to_pio_cycles(duration: Duration) -> u32 {
(clocks::clk_sys_freq() / 1_000_000) / 3 * duration.as_micros() as u32 // parentheses are required to prevent overflow (clocks::clk_sys_freq() / 1_000_000) / 3 * duration.as_micros() as u32 // parentheses are required to prevent overflow
} }
@ -43,6 +45,7 @@ impl<'a, PIO: Instance> PioPwmProgram<'a, PIO> {
/// Pio backed PWM output /// Pio backed PWM output
pub struct PioPwm<'d, T: Instance, const SM: usize> { pub struct PioPwm<'d, T: Instance, const SM: usize> {
sm: StateMachine<'d, T, SM>, sm: StateMachine<'d, T, SM>,
pin: Pin<'d, T>
} }
impl<'d, T: Instance, const SM: usize> PioPwm<'d, T, SM> { impl<'d, T: Instance, const SM: usize> PioPwm<'d, T, SM> {
@ -62,20 +65,20 @@ impl<'d, T: Instance, const SM: usize> PioPwm<'d, T, SM> {
sm.set_config(&cfg); sm.set_config(&cfg);
Self { sm } Self { sm, pin }
} }
/// Enable PWM output /// Enable's the PIO program, continuing the wave generation from the PIO program.
pub fn start(&mut self) { pub fn start(&mut self) {
self.sm.set_enable(true); self.sm.set_enable(true);
} }
/// Disable PWM output /// Stops the PIO program, ceasing all signals from the PIN that were generated via PIO.
pub fn stop(&mut self) { pub fn stop(&mut self) {
self.sm.set_enable(false); self.sm.set_enable(false);
} }
/// Set pwm period /// Sets the pwm period, which is the length of time for each pio wave until reset.
pub fn set_period(&mut self, duration: Duration) { pub fn set_period(&mut self, duration: Duration) {
let is_enabled = self.sm.is_enabled(); let is_enabled = self.sm.is_enabled();
while !self.sm.tx().empty() {} // Make sure that the queue is empty while !self.sm.tx().empty() {} // Make sure that the queue is empty
@ -102,7 +105,8 @@ impl<'d, T: Instance, const SM: usize> PioPwm<'d, T, SM> {
} }
} }
fn set_level(&mut self, level: u32) { /// Set the number of pio cycles to set the wave on high to.
pub fn set_level(&mut self, level: u32) {
self.sm.tx().push(level); self.sm.tx().push(level);
} }
@ -110,4 +114,9 @@ impl<'d, T: Instance, const SM: usize> PioPwm<'d, T, SM> {
pub fn write(&mut self, duration: Duration) { pub fn write(&mut self, duration: Duration) {
self.set_level(to_pio_cycles(duration)); self.set_level(to_pio_cycles(duration));
} }
// Return the state machine and pin.
pub fn release(self) -> (StateMachine<'d, T, SM>, Pin<'d, T>) {
(self.sm, self.pin)
}
} }