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use cast::{u16, u32};
use cortex_m::peripheral::syst::SystClkSource;
use cortex_m::peripheral::SYST;
use embedded_hal::blocking::delay::{DelayMs, DelayUs};
#[derive(Clone)]
pub struct Delay {
scale: u32,
}
const SYSTICK_RANGE: u32 = 0x0100_0000;
impl Delay {
pub fn new(mut syst: SYST) -> Delay {
syst.set_clock_source(SystClkSource::Core);
syst.set_reload(SYSTICK_RANGE - 1);
syst.clear_current();
syst.enable_counter();
Delay { scale: 5 }
}
}
impl DelayMs<u32> for Delay {
fn delay_ms(&mut self, mut ms: u32) {
const MAX_MS: u32 = 0x0000_FFFF;
while ms != 0 {
let current_ms = if ms <= MAX_MS { ms } else { MAX_MS };
self.delay_us(current_ms * 1_000);
ms -= current_ms;
}
}
}
impl DelayMs<u16> for Delay {
fn delay_ms(&mut self, ms: u16) {
self.delay_us(u32(ms) * 1_000);
}
}
impl DelayMs<u8> for Delay {
fn delay_ms(&mut self, ms: u8) {
self.delay_ms(u16(ms));
}
}
impl DelayUs<u32> for Delay {
fn delay_us(&mut self, us: u32) {
const MAX_TICKS: u32 = 0x007F_FFFF;
let mut total_ticks = us * self.scale;
while total_ticks != 0 {
let current_ticks = if total_ticks <= MAX_TICKS {
total_ticks
} else {
MAX_TICKS
};
let start_count = SYST::get_current();
total_ticks -= current_ticks;
while (start_count.wrapping_sub(SYST::get_current()) % SYSTICK_RANGE) < current_ticks {}
}
}
}
impl DelayUs<u16> for Delay {
fn delay_us(&mut self, us: u16) {
self.delay_us(u32(us))
}
}
impl DelayUs<u8> for Delay {
fn delay_us(&mut self, us: u8) {
self.delay_us(u32(us))
}
}
#[cfg(test)]
mod tests {
#[test]
fn nothing() {
}
}