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modify tic.c to chec if interrupts are enabled, rename us_between_ticks to us until_next_tick

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This commit is contained in:
Jerry Needell 2018-04-19 22:25:48 -04:00
parent 3399d541c3
commit 16bb40b110
1 changed files with 9 additions and 6 deletions
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15
ports/atmel-samd/tick.c
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@ -58,21 +58,24 @@ void tick_init() {
void tick_delay(uint32_t us) {
uint32_t ticks_per_us = common_hal_mcu_processor_get_frequency() / 1000 / 1000;
uint32_t us_between_ticks = SysTick->VAL / ticks_per_us;
uint32_t us_until_next_tick = SysTick->VAL / ticks_per_us;
uint32_t start_tick;
while (us > 1000) {
// check if interrupts are disabled
if(__get_PRIMASK())
return; // if not just return
start_tick=SysTick->VAL; // wait for SysTick->VAL to RESET
while (SysTick->VAL < start_tick) {}
us -= us_between_ticks;
us_between_ticks = 1000;
us -= us_until_next_tick;
us_until_next_tick = 1000;
}
if(us&&(us < us_between_ticks)){
while (SysTick->VAL > ((us_between_ticks - us) * ticks_per_us)) {}
if(us&&(us < us_until_next_tick)){
while (SysTick->VAL > ((us_until_next_tick - us) * ticks_per_us)) {}
}
else {
start_tick=SysTick->VAL; // wait for SysTick->VAL to RESET
while (SysTick->VAL < start_tick) {}
us -= us_between_ticks;
us -= us_until_next_tick;
if(us){
while (SysTick->VAL > ((1000 - us) * ticks_per_us)) {}
}