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Fix integer overflow in microseconds delay, typos #16

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Fix integer overflow in microseconds delay, typos #16

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844ee7e
Fix microseconds delay, typos
rkarabut Aug 23, 2021
69161c5
Expand count parameters to u64 to accomodate values > ~1000s
rkarabut Aug 23, 2021
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20 changes: 9 additions & 11 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -23,8 +23,8 @@

/// Internal function to implement a variable busy-wait loop.
/// # Arguments
/// * 'count' - an i32, the number of times to cycle the loop.
pub fn delay(count: u32) {
/// * 'count' - a u64, the number of times to cycle the loop.
pub fn delay(count: u64) {
// Our asm busy-wait takes a 16 bit word as an argument,
// so the max number of loops is 2^16
let outer_count = count / 65536;
Expand All @@ -46,23 +46,21 @@ pub fn delay(count: u32) {
:)}
}

///delay for N miliseconds
///delay for N milliseconds
/// # Arguments
/// * 'ms' - an u32, number of milliseconds to busy-wait
pub fn delay_ms(ms: u32) {
/// * 'ms' - a u64, number of milliseconds to busy-wait
pub fn delay_ms(ms: u64) {
// microseconds
let us = ms * 1000;
delay_us(us);
}

///delay for N microseconds
/// # Arguments
/// * 'ms' - an u32, number of microseconds to busy-wait
pub fn delay_us(us: u32) {
// picoseconds
let ps = us * 1000;
let ps_lp = 1000000000 / (avr_config::CPU_FREQUENCY_HZ / 4);
let loops = (ps / ps_lp) as u32;
/// * 'us' - a u64, number of microseconds to busy-wait
pub fn delay_us(us: u64) {
let us_in_loop = (avr_config::CPU_FREQUENCY_HZ / 1000000 / 4) as u64;
let loops = us * us_in_loop;
delay(loops);
}

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