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PWM output calculations dynamic based on clock speed

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This commit is contained in:
blckmn 2017-06-28 21:59:42 +10:00
parent 14f82e2a63
commit b9ebf8f4fd
11 changed files with 117 additions and 139 deletions
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29
src/main/drivers/timer.c
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@ -229,16 +229,16 @@ void timerNVICConfigure(uint8_t irq)
NVIC_Init(&NVIC_InitStructure);
}
void configTimeBase(TIM_TypeDef *tim, uint16_t period, uint8_t mhz)
void configTimeBase(TIM_TypeDef *tim, uint16_t period, uint32_t hz)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
TIM_TimeBaseStructure.TIM_Period = (period - 1) & 0xffff; // AKA TIMx_ARR
TIM_TimeBaseStructure.TIM_Period = (period - 1) & 0xFFFF; // AKA TIMx_ARR
// "The counter clock frequency (CK_CNT) is equal to f CK_PSC / (PSC[15:0] + 1)." - STM32F10x Reference Manual 14.4.11
// Thus for 1Mhz: 72000000 / 1000000 = 72, 72 - 1 = 71 = TIM_Prescaler
TIM_TimeBaseStructure.TIM_Prescaler = (SystemCoreClock / timerClockDivisor(tim) / ((uint32_t)mhz * 1000000)) - 1;
TIM_TimeBaseStructure.TIM_Prescaler = (timerClock(tim) / hz) - 1;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
@ -246,9 +246,9 @@ void configTimeBase(TIM_TypeDef *tim, uint16_t period, uint8_t mhz)
}
// old interface for PWM inputs. It should be replaced
void timerConfigure(const timerHardware_t *timerHardwarePtr, uint16_t period, uint8_t mhz)
void timerConfigure(const timerHardware_t *timerHardwarePtr, uint16_t period, uint32_t hz)
{
configTimeBase(timerHardwarePtr->tim, period, mhz);
configTimeBase(timerHardwarePtr->tim, period, hz);
TIM_Cmd(timerHardwarePtr->tim, ENABLE);
uint8_t irq = timerInputIrq(timerHardwarePtr->tim);
@ -849,14 +849,19 @@ uint16_t timerDmaSource(uint8_t channel)
uint16_t timerGetPrescalerByDesiredMhz(TIM_TypeDef *tim, uint16_t mhz)
{
// protection here for desired MHZ > timerClock???
if ((uint32_t)(mhz * 1000000) > timerClock(tim)) {
return 0;
}
return (uint16_t)(round((timerClock(tim) / (mhz * 1000000)) - 1));
return timerGetPrescalerByDesiredHertz(tim, MHZ_TO_HZ(mhz));
}
uint16_t timerGetPeriodByPrescaler(TIM_TypeDef *tim, uint16_t prescaler, uint32_t hertz)
uint16_t timerGetPeriodByPrescaler(TIM_TypeDef *tim, uint16_t prescaler, uint32_t hz)
{
return ((uint16_t)((timerClock(tim) / (prescaler + 1)) / hertz));
return ((uint16_t)((timerClock(tim) / (prescaler + 1)) / hz));
}
uint16_t timerGetPrescalerByDesiredHertz(TIM_TypeDef *tim, uint32_t hz)
{
// protection here for desired hertz > SystemCoreClock???
if (hz > timerClock(tim)) {
return 0;
}
return (uint16_t)((timerClock(tim) + hz / 2 ) / hz) - 1;
}