Posted on March 16, 2015 at 15:53
I dont know if DMA + PWM would fix this problem.. I dont know if it would even work, but I though that it would be easy, a simple thing.Any tip or help would be welcomed.Thanks in advance. #adc #pwm #dma #stm32f2 #tim5
Hi, I need to modify a PWM inside an interrupt, I though that It would be easy, just changing CCR2 to the new desired value but it is not working properly.
The change is not happening each pulse, it is a bit random.. not sure why. If i set 3000, it works right, if I set 17500 it works right, but if i set a condition to change from one to the other value then it doesnt work because it doesnt change in each interrupt, at it is even a bit random (image below)...My code is simple..., after each TIM5 interrupt I want a new PWM (in this example 2 values, in my real code more values, but I wanted something easy to show here)void TIM5_IRQHandler(void) { if (TIM_GetITStatus(TIM5, TIM_IT_Update) != RESET) {static int a=1;
a^=1; if(a) TIM9->CCR2=3000; else TIM9->CCR2=17500; TIM9->CNT=0;TIM_ClearITPendingBit(TIM5, TIM_IT_Update);
}}Here is the initialization of the ports (that's working right)void TIM5_Configuration(void){ TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM5, ENABLE); TIM_TimeBaseStructure.TIM_Period =5200; TIM_TimeBaseStructure.TIM_Prescaler = 0; TIM_TimeBaseStructure.TIM_ClockDivision = 0; TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; TIM_TimeBaseInit(TIM5, &TIM_TimeBaseStructure); TIM_PrescalerConfig(TIM5, 2 , TIM_PSCReloadMode_Immediate); TIM_ITConfig(TIM5,TIM_IT_Update , ENABLE); TIM_Cmd(TIM5, ENABLE); NVIC_InitTypeDef NVIC_InitStructure; NVIC_InitStructure.NVIC_IRQChannel = TIM5_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure);}void TIM9_PWM_Configuration2(void){ GPIO_InitTypeDef GPIO_InitStructure; TIM_OCInitTypeDef TIM_OCInitStructure; TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM9, ENABLE); GPIO_InitStructure.GPIO_Pin = pinO; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; GPIO_Init(portO, &GPIO_InitStructure); GPIO_PinAFConfig(portO, O_SOURCE, GPIO_AF_TIM9); TIM_TimeBaseStructure.TIM_Period =5200*6; TIM_TimeBaseStructure.TIM_RepetitionCounter =0; TIM_TimeBaseStructure.TIM_Prescaler = 0; TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; TIM_TimeBaseInit(TIM9, &TIM_TimeBaseStructure);// TIM_PrescalerConfig(TIM9, 2 , TIM_PSCReloadMode_Immediate); TIM_ITConfig(TIM9,TIM_IT_Update , ENABLE); /* Enable TIM9 Preload register on ARR */ TIM_ARRPreloadConfig(TIM9, ENABLE); /* TIM PWM1 Mode configuration */ TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; TIM_OCInitStructure.TIM_Pulse = 1000; TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; TIM_OC2Init(TIM9, &TIM_OCInitStructure); TIM_OC2PreloadConfig(TIM9, TIM_OCPreload_Enable); TIM_Cmd(TIM9, ENABLE);}Bank2 CH 8 is the PWM TIM 9 CH2 while Bank2 ch 15 is the IRQ (TIM 5)I dont know if DMA + PWM would fix this problem.. I dont know if it would even work, but I though that it would be easy, a simple thing.Any tip or help would be welcomed.Thanks in advance. #adc #pwm #dma #stm32f2 #tim5
