STM32F072 Alternate PWM

Posted on January 28, 2015 at 17:22

Hi guys.

I'm having a little issue about using 6 pwm on different timers, on my STM32F072.

Application is:

a board with an adjustable sensor. The adjust phase works with a generation of pwm, changing the duty cycle until a signal on another port change.

This is the actual working code, with the PWM on timer 17

/* Installing pwm and definitions */

&sharpdefine HW_TIM_PWM_OUT_DIS        TIM_CtrlPWMOutputs(TIM17, DISABLE)

&sharpdefine HW_TIM_PWM_DIS            TIM_Cmd(TIM17, DISABLE)

&sharpdefine HW_TIM_PWM_ENA            TIM_Cmd(TIM17, ENABLE)

&sharpdefine HW_TIM_PWM_CLR            TIM_SetCounter(TIM17, 0)

&sharpdefine HW_TIM_PWM_INS(duty) \

{ \

TIM_TimeBaseInitTypeDef loc; \

    TIM_OCInitTypeDef oloc; \

                                                        /* TIM clock enable */ \

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM17, ENABLE); \

                                                        /* Time base configuration */ \

    loc.TIM_Period = 480; \

    loc.TIM_Prescaler = (word) (SystemCoreClock  / 4800000) - 1; \

    loc.TIM_ClockDivision = TIM_CKD_DIV1; \

    loc.TIM_CounterMode = TIM_CounterMode_Up; \

    TIM_TimeBaseInit(TIM17, &loc); \

                                                        /* Output compare PWM 1 */ \

    TIM_OCStructInit(&oloc); \

    oloc.TIM_OCMode = TIM_OCMode_PWM1; \

    oloc.TIM_Pulse = ((dword)480 * (dword)duty + 128UL) / 256UL; \

    oloc.TIM_OutputState = TIM_OutputState_Enable; \

    TIM_OC1Init(TIM17, &oloc); \

    TIM_CtrlPWMOutputs(TIM17, ENABLE); \

On calibration phase, this is what I actually do (with success), on a cycle where ''duty_n'' changes as described before

HW_TIM_PWM_INS(duty_n);

HW_TIM_PWM_CLR;

HW_TIM_PWM_ENA;

Hope you understand.

Now, I have to do the exact same thing for another pwm, tied on timer 2.

My issue is: since there's no way to set TIM2 on function

TIM_CtrlPWMOutputs

what can I do as ''workaround''?

Ps. I found the TIM_CCxCmd routine on library, but it's not working. Damn. Help me!

#pwm #stm32 #pwm #timer-synchronization