/**
* @brief Configures the TIM2 Trigger as External Clock.
* @param TIM2_TIxExternalCLKSource : Specifies Trigger source.
* This parameter can be one of the @ref TIM2_TIxExternalCLK1Source_TypeDef enumeration.
* @param TIM2_ICPolarity : Specifies the TIx Polarity.
* This parameter can be @ref TIM2_ICPolarity_TypeDef enumeration.
* @param ICFilter : Specifies the filter value.
* This parameter must be a value between 0x00 and 0x0F
* @retval None
*/
void TIM2_TIxExternalClockConfig(TIM2_TIxExternalCLK1Source_TypeDef TIM2_TIxExternalCLKSource,
TIM2_ICPolarity_TypeDef TIM2_ICPolarity,
uint8_t ICFilter)
{
/* Check the parameters */
assert_param(IS_TIM2_TIXCLK_SOURCE(TIM2_TIxExternalCLKSource));
assert_param(IS_TIM2_IC_POLARITY(TIM2_ICPolarity));
assert_param(IS_TIM2_IC_FILTER(ICFilter));
/* Configure the TIM2 Input Clock Source */
if (TIM2_TIxExternalCLKSource == TIM2_TIxExternalCLK1Source_TI2)
{
TI2_Config(TIM2_ICPolarity, TIM2_ICSelection_DirectTI, ICFilter);
}
else
{
TI1_Config(TIM2_ICPolarity, TIM2_ICSelection_DirectTI, ICFilter);
}
/* Select the Trigger source */
TIM2_SelectInputTrigger((TIM2_TRGSelection_TypeDef)TIM2_TIxExternalCLKSource);
/* Select the External clock mode1 */
TIM2->SMCR |= (uint8_t)(TIM2_SlaveMode_External1);
}
/**
* @brief Configure TIM1,2,3 peripherals
* @param None
* @retval None
*/
static void TIM_Config(void)
{
/* TIM1 configuration:
- TIM1CLK is set to 2 MHz, the TIM2 Prescaler is equal to 15 so the TIM1 counter
clock used is 2 MHz / (15 + 1) = 125 000 Hz
- TIM1 Channel 1 output frequency = TIM1CLK / (TIM1_PERIOD + 1) * (TIM1_PRESCALER + 1)
= 2 000 000 / 256 * 16 = 488.28 Hz */
/* Time Base configuration */
TIM1_TimeBaseInit(TIM1_PRESCALER, TIM1_CounterMode_Up, TIM1_PERIOD, TIM1_REPETITION_COUNTER);
/* TIM1 Channel 1 Configuration in PWM2 mode */
TIM1_OC1Init(TIM1_OCMode_PWM2, TIM1_OutputState_Enable, TIM1_OutputNState_Disable, TIM1_CCR1_VAL,
TIM1_OCPolarity_Low, TIM1_OCNPolarity_Low, TIM1_OCIdleState_Set, TIM1_OCNIdleState_Set);
/* Master Mode selection: Update event */
TIM1_SelectOutputTrigger(TIM1_TRGOSource_Update);
/* TIM2 configuration:
- TIM2 is connected to TIM1 Update so TIM2CLK is equal to
TIM1 output clock / (TIM1_REPETITION_COUNTER + 1) = 488.28 / 5 = 97.65 Hz
- TIM2 Prescaler is equal to 1 so the TIM2 counter clock used is 97.65 / 1 = 97.65 Hz
- TIM2 Channel 1 output frequency = TIM2CLK / (TIM2_PERIOD + 1) * TIM2_Prescaler
= 97.65 / 3 * 1 = 32.55 Hz */
/* Time Base configuration */
TIM2_TimeBaseInit(TIM2_Prescaler_1, TIM2_CounterMode_Up, TIM2_PERIOD);
TIM2_OC1Init(TIM2_OCMode_PWM2, TIM2_OutputState_Enable, TIM2_CCR1_VAL,
TIM2_OCPolarity_Low, TIM2_OCIdleState_Reset);
/* TIM2 Slave Mode selection: Gated mode */
TIM2_SelectSlaveMode(TIM2_SlaveMode_Gated);
TIM2_SelectInputTrigger(TIM2_TRGSelection_TIM1);
/* TIM3 configuration:
- TIM3 is connected to TIM1 Update so TIM3CLK is equal to
TIM1 output clock / (TIM1_REPETITION_COUNTER + 1) = 488.28 / 5 = 97.65 Hz
- TIM3 Prescaler is equal to 1 so the TIM3 counter clock used is 97.65 / 1 = 97.65 Hz
- TIM3 Channel 1 output frequency = TIM3CLK / (TIM3_PERIOD + 1) * TIM3Prescaler
= 97.65 / 4 * 1 = 24.41 Hz */
/* Time Base configuration */
TIM3_TimeBaseInit(TIM3_Prescaler_1, TIM3_CounterMode_Up, TIM3_PERIOD);
TIM3_OC1Init(TIM3_OCMode_PWM2, TIM3_OutputState_Enable, TIM3_CCR1_VAL,
TIM3_OCPolarity_Low, TIM3_OCIdleState_Reset);
/* TIM3 Slave Mode selection: Gated mode */
TIM3_SelectSlaveMode(TIM3_SlaveMode_Gated);
TIM3_SelectInputTrigger(TIM3_TRGSelection_TIM1);
/* Main Output Enable */
TIM1_CtrlPWMOutputs(ENABLE);
TIM2_CtrlPWMOutputs(ENABLE);
TIM3_CtrlPWMOutputs(ENABLE);
/* TIM2 counter enable */
TIM2_Cmd(ENABLE);
/* TIM3 counter enable */
TIM3_Cmd(ENABLE);
/* TIM1 counter enable */
TIM1_Cmd(ENABLE);
}
