STM32F072 Alternate PWM

[d239955_stm1_stmicro_com]

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

[Tesla DeLorean]

Posted on January 28, 2015 at 17:42

Hope you understand.

Not really.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''? Switch the pin between GPIO and AF settings?

[d239955_stm1_stmicro_com]

Posted on January 29, 2015 at 08:41

What's the part you didn't understand? Maybe I could attach the whole C project 😉

Anyway, about your suggestion... I'll try and I'll let you know! Thanks

[Tesla DeLorean]

Posted on January 29, 2015 at 14:23

What's the part you didn't understand? Maybe I could attach the whole C project 😉

Describe the unknown unknowns? Showing me the code tells me what you've done, and isn't working on the other timer, it doesn't show me what you want to achieve. Draw a diagram of the signalling you want to come out of the pins, and how enabling/disabling the PWM outputs impacts that. Draw a diagram of the signal from the timer that isn't doing what you want, and mark clearly the behaviour you don't want contrasting it to the behaviour you do want.

[d239955_stm1_stmicro_com]

Posted on January 29, 2015 at 17:36

Basically, I wanted to have a workaround for the CtrlPWMOutputs routine.

Your suggestion does work, so... problem solved! Thanks for support and patience!