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[STM32F4xx] PWM frequency calculation correction 

All STM32F4xx mcu with a clock frequency larger than 100MHz (F405, F407,
F429, F446), have two different maximal timer frequencies: SYSCLK and
SYSCLK/2. The pwm frequency calculation was based only on SYSCLK. For
Nucleo target this was OK but for some Discovery and some other targets
the pwm frequency was partly wrong, depending on the used timer.
This PR reads out the specific timer frequency and calculates the
correct pwm frequency.
pull/1150/head
ohagendorf 2015-06-03 01:02:38 +02:00
parent 7a1d25e3df
commit 0abf0f3e41
1 changed files with 71 additions and 2 deletions
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73
libraries/mbed/targets/hal/TARGET_STM/TARGET_STM32F4/pwmout_api.c
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@ -165,7 +165,9 @@ void pwmout_period_ms(pwmout_t* obj, int ms)
void pwmout_period_us(pwmout_t* obj, int us)
{
TimHandle.Instance = (TIM_TypeDef *)(obj->pwm);
RCC_ClkInitTypeDef RCC_ClkInitStruct;
uint32_t PclkFreq;
uint32_t APBxCLKDivider;
float dc = pwmout_read(obj);
__HAL_TIM_DISABLE(&TimHandle);
@ -173,8 +175,75 @@ void pwmout_period_us(pwmout_t* obj, int us)
// Update the SystemCoreClock variable
SystemCoreClockUpdate();
HAL_RCC_GetClockConfig(&RCC_ClkInitStruct, &PclkFreq);
switch (obj->pwm) {
case PWM_1:
PclkFreq = HAL_RCC_GetPCLK2Freq();
APBxCLKDivider = RCC_ClkInitStruct.APB2CLKDivider;
break;
case PWM_2:
PclkFreq = HAL_RCC_GetPCLK1Freq();
APBxCLKDivider = RCC_ClkInitStruct.APB1CLKDivider;
break;
case PWM_3:
PclkFreq = HAL_RCC_GetPCLK1Freq();
APBxCLKDivider = RCC_ClkInitStruct.APB1CLKDivider;
break;
case PWM_4:
PclkFreq = HAL_RCC_GetPCLK1Freq();
APBxCLKDivider = RCC_ClkInitStruct.APB1CLKDivider;
break;
#if defined(TIM8_BASE)
case PWM_8:
PclkFreq = HAL_RCC_GetPCLK2Freq();
APBxCLKDivider = RCC_ClkInitStruct.APB2CLKDivider;
break;
#endif
case PWM_9:
PclkFreq = HAL_RCC_GetPCLK2Freq();
APBxCLKDivider = RCC_ClkInitStruct.APB2CLKDivider;
break;
case PWM_10:
PclkFreq = HAL_RCC_GetPCLK2Freq();
APBxCLKDivider = RCC_ClkInitStruct.APB2CLKDivider;
break;
case PWM_11:
PclkFreq = HAL_RCC_GetPCLK2Freq();
APBxCLKDivider = RCC_ClkInitStruct.APB2CLKDivider;
break;
#if defined(TIM13_BASE)
case PWM_13:
PclkFreq = HAL_RCC_GetPCLK1Freq();
APBxCLKDivider = RCC_ClkInitStruct.APB1CLKDivider;
break;
#endif
#if defined(TIM14_BASE)
case PWM_14:
PclkFreq = HAL_RCC_GetPCLK1Freq();
APBxCLKDivider = RCC_ClkInitStruct.APB1CLKDivider;
break;
#endif
default:
return;
}
TimHandle.Init.Period = us - 1;
TimHandle.Init.Prescaler = (uint16_t)(SystemCoreClock / 1000000) - 1; // 1 µs tick
if (APBxCLKDivider == RCC_HCLK_DIV1)
TimHandle.Init.Prescaler = (uint16_t)((PclkFreq*2) / 1000000) - 1; // 1 µs tick
else
TimHandle.Init.Prescaler = (uint16_t)((PclkFreq) / 1000000) - 1; // 1 µs tick
TimHandle.Init.ClockDivision = 0;
TimHandle.Init.CounterMode = TIM_COUNTERMODE_UP;
HAL_TIM_PWM_Init(&TimHandle);