STM32F4 PWM starting with different Polarity and shift time state

[tropinka06]

Posted on May 16, 2015 at 11:29

Hi.

I work on STM32F4 MCU. For current project I work with 3 PWM are configured on TIM1 and Channels 1, 2, 3, GPIOs PE9, PE11, PE13.Every channel configured with 60 degrees shift. When I do ''Enable'' for all channels

TIM_CCxCmd

(TIM1, TIM_Channel_1, TIM_CCx_Enable);

TIM_CCxCmd

(TIM1, TIM_Channel_2, TIM_CCx_Enable);

TIM_CCxCmd

(TIM1, TIM_Channel_3, TIM_CCx_Enable); they are work with 60 degres shift as defined, but every start pulse can be started from different state - high or low in the 0-120 degrees time.How can I define PWM output that Channel1 will start every time with ''Enable'' channel and from low to high state (0 degrees delay), not shifted between 0-120 degrees.Thanks.This is my part code.void

GPIO_Configuration

(void){    GPIO_InitTypeDef GPIO_InitStructure;        // GPIOE clock enable   

RCC_AHB1PeriphClockCmd

(RCC_AHB1Periph_GPIOE, ENABLE);    //------------------------------------------------------------------------        // PWM GPIOs    // Connect TIM1 pins   

GPIO_PinAFConfig

(GPIOE, GPIO_PinSource9,  GPIO_AF_TIM1); // PE9  TIM1_CH1     

GPIO_PinAFConfig

(GPIOE, GPIO_PinSource11, GPIO_AF_TIM1); // PE11 TIM1_CH2    

GPIO_PinAFConfig

(GPIOE, GPIO_PinSource13, GPIO_AF_TIM1); // PE13 TIM1_CH3         GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_11 | GPIO_Pin_13;    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_DOWN;    

GPIO_Init

(GPIOE, &GPIO_InitStructure);}void

TIM1_Configuration

(uint32_t PWM_Frequency){    RCC_ClocksTypeDef RCC_ClocksStructure;    TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;    TIM_OCInitTypeDef  TIM_OCInitStructure;    int Prescaler, Period;    uint32_t TimerFrequency = 0;        // enable peripheral clock for TIM1   

RCC_APB2PeriphClockCmd

(RCC_APB2Periph_TIM1, ENABLE);    // Get clocks

RCC_GetClocksFreq

(&RCC_ClocksStructure);    // if(TIMx == TIM1) TimerFrequency = RCC_ClocksStructure.HCLK_Frequency;    Prescaler = 1;    Period = TimerFrequency / 2 / PWM_Frequency;   // KHz    // The toggle halves the frequency        /* Time base configuration */    TIM_TimeBaseStructure.TIM_Period = Period - 1;    TIM_TimeBaseStructure.TIM_Prescaler = Prescaler - 1;    TIM_TimeBaseStructure.TIM_ClockDivision = 0;    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;   

TIM_TimeBaseInit

(TIM1, &TIM_TimeBaseStructure);        /* Output Compare Toggle Mode configuration: Channel 1, 2 and 3 */    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;    TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;    TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCPolarity_High;        /* Default unused fields TIM1 more sensitive */    TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;    TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCNIdleState_Reset;       /* Don't want to set 0 or Period, but have 3 points at 120 degrees from each other */    TIM_OCInitStructure.TIM_Pulse = ((Period * 1) / 3) - 1;   

TIM_OC1Init

(TIM1, &TIM_OCInitStructure);        TIM_OCInitStructure.TIM_Pulse = ((Period * 2) / 3) - 1;   

TIM_OC2Init

(TIM1, &TIM_OCInitStructure);        TIM_OCInitStructure.TIM_Pulse = ((Period * 3) / 3) - 1;   

TIM_OC3Init

(TIM1, &TIM_OCInitStructure);       /* Enable pins, TIM1 more sensitive */   

TIM_CtrlPWMOutputs

(TIM1, ENABLE);     /* Configures the TIM1 Update Request Interrupt source (SETS the CR1->URS bit)*/        

TIM_UpdateRequestConfig

(TIM1,TIM_UpdateSource_Global);        /* TIM1 enable counter */   

TIM_Cmd

(TIM1, ENABLE);    // Disable Channels   

TIM_CCxCmd

(TIM1, TIM_Channel_1, TIM_CCx_Disable);   

TIM_CCxCmd

(TIM1, TIM_Channel_2, TIM_CCx_Disable);   

TIM_CCxCmd

(TIM1, TIM_Channel_3, TIM_CCx_Disable);}