在之前做了开箱与串口打印,这次就做一个呼吸灯,用PWM波驱动开发板自带的LED,开发板的LED是在B14,B15 io口,
用TIM1驱动,关键代理如下
- void TIM1_Configure(void)
- {
- RCC_ClocksTypeDef RCC_Clocks;
- GPIO_InitTypeDef GPIO_InitStruct;
- TIM_OCInitTypeDef TIM_OCInitStruct;
- TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
- uint32_t TIM_ClockFrequency = 0;
- uint32_t HPRE = 0, PPRE2 = 0;
- uint32_t TimerPeriod = 0, Channel1Pulse = 0, Channel2Pulse = 0, Channel3Pulse = 0;
- HPRE = READ_BIT(RCC->CFGR, RCC_CFGR_HPRE) >> RCC_CFGR_HPRE_Pos;
- PPRE2 = READ_BIT(RCC->CFGR, RCC_CFGR_PPRE2) >> RCC_CFGR_PPRE2_Pos;
- RCC_GetClocksFreq(&RCC_Clocks);
- if (HPRE < 8)
- {
- if (PPRE2 < 4)
- {
- TIM_ClockFrequency = RCC_Clocks.PCLK1_Frequency;
- }
- else
- {
- TIM_ClockFrequency = RCC_Clocks.PCLK1_Frequency * 2;
- }
- }
- else
- {
- if (PPRE2 < 4)
- {
- TIM_ClockFrequency = RCC_Clocks.PCLK1_Frequency * 2;
- }
- else
- {
- TIM_ClockFrequency = RCC_Clocks.PCLK1_Frequency * 4;
- }
- }
- /* Compute the value to be set in ARR regiter to generate signal frequency at 100 Khz */
- TimerPeriod = TIM_ClockFrequency / 100000;
- /* Compute CCR1 value to generate a duty cycle at 75% for channel 1 */
- Channel1Pulse = (uint32_t)750 * TimerPeriod / 1000;
- /* Compute CCR2 value to generate a duty cycle at 50% for channel 2 */
- Channel2Pulse = (uint32_t)500 * TimerPeriod / 1000;
- /* Compute CCR3 value to generate a duty cycle at 25% for channel 3 */
- Channel3Pulse = (uint32_t)250 * TimerPeriod / 1000;
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
- TIM_TimeBaseStructInit(&TIM_TimeBaseInitStruct);
- TIM_TimeBaseInitStruct.TIM_Prescaler = 0;
- TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
- TIM_TimeBaseInitStruct.TIM_Period = TimerPeriod;
- TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_Div1;
- TIM_TimeBaseInitStruct.TIM_RepetitionCounter = 0;
- TIM_TimeBaseInit(TIM1, &TIM_TimeBaseInitStruct);
- TIM_OCStructInit(&TIM_OCInitStruct);
- TIM_OCInitStruct.TIM_OCMode = TIM_OCMode_PWM1;
- TIM_OCInitStruct.TIM_OutputState = TIM_OutputState_Enable;
- TIM_OCInitStruct.TIM_Pulse = 0;
- TIM_OCInitStruct.TIM_OCPolarity = TIM_OCPolarity_High;
- TIM_OCInitStruct.TIM_OCIdleState = TIM_OCIdleState_Set;
- TIM_OCInitStruct.TIM_Pulse = Channel1Pulse;
- TIM_OC1Init(TIM1, &TIM_OCInitStruct);
- TIM_OCInitStruct.TIM_Pulse = Channel2Pulse;
- TIM_OC2Init(TIM1, &TIM_OCInitStruct);
- TIM_OCInitStruct.TIM_Pulse = Channel3Pulse;
- TIM_OC3Init(TIM1, &TIM_OCInitStruct);
- RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE);
- GPIO_PinAFConfig(GPIOB, GPIO_PinSource14, GPIO_AF_7); /* TIM1_CH1 */
- GPIO_PinAFConfig(GPIOB, GPIO_PinSource15, GPIO_AF_7); /* TIM1_CH2 */
- GPIO_StructInit(&GPIO_InitStruct);
- GPIO_InitStruct.GPIO_Pin = GPIO_Pin_14 | GPIO_Pin_15 ;
- GPIO_InitStruct.GPIO_Speed = GPIO_Speed_High;
- GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_PP;
- GPIO_Init(GPIOB, &GPIO_InitStruct);
- TIM_Cmd(TIM1, ENABLE);
- TIM_CtrlPWMOutputs(TIM1, ENABLE);
- }
然后在例程中的这里改一下
- void TIM1_PWM_Output_Sample(void)
- {
- uint16_t i =0;
- printf("\r\nTest %s", __FUNCTION__);
- TIM1_Configure();
- while (1)
- {
- TIM1->CCR1 = 1440 - (i++%1440);
- TIM1->CCR2 = (i++%1440);
- PLATFORM_DelayMS(1);
- }
- }
下面上效果
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