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Invert duty cycle intensity

This commit is contained in:
Lucian Copeland 2020-01-22 18:47:41 -05:00
parent 36792926d2
commit e9f9cee4d6
1 changed files with 3 additions and 2 deletions
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5
ports/stm32f4/common-hal/pulseio/PWMOut.c
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@ -68,8 +68,9 @@ STATIC uint32_t timer_get_source_freq(uint32_t tim_id) {
} }
STATIC uint32_t timer_get_internal_duty(uint16_t duty, uint32_t period) { STATIC uint32_t timer_get_internal_duty(uint16_t duty, uint32_t period) {
//duty cycle is duty/0xFFFF fraction x (number of pulses per period) //duty cycle is (0xFFFF - duty)/0xFFFF fraction x (number of pulses per period)
return (duty*period) / ((1 << 16) - 1); //Note that pulses are inverted, so duty cycle is inverted
return ((0xFFFF - duty)*period) / ((1 << 16) - 1);
} }
STATIC void timer_get_optimal_divisors(uint32_t*period, uint32_t*prescaler, STATIC void timer_get_optimal_divisors(uint32_t*period, uint32_t*prescaler,