diff options
Diffstat (limited to 'ports/atmel-samd/tick.c')
| -rw-r--r-- | ports/atmel-samd/tick.c | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/ports/atmel-samd/tick.c b/ports/atmel-samd/tick.c index f5fd57f5d..27b5f05b4 100644 --- a/ports/atmel-samd/tick.c +++ b/ports/atmel-samd/tick.c @@ -52,21 +52,21 @@ void SysTick_Handler(void) { void tick_init() { uint32_t ticks_per_ms = common_hal_mcu_processor_get_frequency() / 1000; - SysTick_Config(ticks_per_ms); + SysTick_Config(ticks_per_ms-1); NVIC_EnableIRQ(SysTick_IRQn); } 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; - uint64_t start_ms = ticks_ms; - while (us > 1000) { - while (ticks_ms == start_ms) {} - us -= us_between_ticks; - start_ms = ticks_ms; - us_between_ticks = 1000; + uint32_t us_until_next_tick = SysTick->VAL / ticks_per_us; + uint32_t start_tick; + while (us >= us_until_next_tick) { + start_tick=SysTick->VAL; // wait for SysTick->VAL to RESET + while (SysTick->VAL < start_tick) {} + us -= us_until_next_tick; + us_until_next_tick = 1000; } - while (SysTick->VAL > ((us_between_ticks - us) * ticks_per_us)) {} + while (SysTick->VAL > ((us_until_next_tick - us) * ticks_per_us)) {} } // us counts down! |