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sys_timer: Add fn to retrieve ts in us resolution

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This commit is contained in:
linuswck 2024-10-10 13:31:20 +08:00
parent bd72c382b0
commit 253f4410ee
1 changed files with 14 additions and 1 deletions
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15
src/device/sys_timer.rs
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@ -2,7 +2,7 @@ use core::{cell::RefCell, ops::Deref};
use cortex_m::{interrupt::Mutex, peripheral::syst::SystClkSource};
use cortex_m_rt::exception;
use stm32f4xx_hal::{pac::SYST, rcc::Clocks};
use stm32f4xx_hal::{pac::{SYST, Peripherals}, rcc::Clocks};
/// Rate in Hz
const TIMER_RATE: u32 = 1000;
@ -10,9 +10,13 @@ const TIMER_RATE: u32 = 1000;
const TIMER_DELTA: u32 = 1000 / TIMER_RATE;
/// Elapsed time in milliseconds
static TIMER_MS: Mutex<RefCell<u32>> = Mutex::new(RefCell::new(0));
static mut US_COUNT: u32 = 168;
/// Setup SysTick exception
pub fn setup(mut syst: SYST, clocks: Clocks) {
unsafe {
US_COUNT = clocks.hclk().to_MHz()
}
syst.set_clock_source(SystClkSource::Core);
syst.set_reload(clocks.hclk().to_Hz() / TIMER_RATE - 1);
syst.enable_counter();
@ -32,6 +36,15 @@ pub fn now() -> u32 {
cortex_m::interrupt::free(|cs| *TIMER_MS.borrow(cs).borrow().deref())
}
/// Obtain current time in milliseconds + microseconds
pub fn now_precise() -> (u32, u32) {
let ms = now();
unsafe {
let us = (Peripherals::steal().STK.load.read().bits() - Peripherals::steal().STK.val.read().bits()) / US_COUNT;
(ms, us)
}
}
/// block for `amount` milliseconds
pub fn sleep(amount: u32) {
if amount == 0 {