PWM on PA8 STM32

cpinkstone · ‎2009-07-09

Posted on July 09, 2009 at 11:02

PWM on PA8 STM32

cpinkstone · ‎2011-05-17

Posted on May 17, 2011 at 12:48

Dear All,

I'm trying to get a 4KHz square wave out of PA8 using TIM1 in PWM mode.

I've tried the various keil and st examples based on timer 3 but I having trouble gettting this working on TIM1.

Is there something extra I've got to configure on timer 1?

Could anyone post some source for this?

Thanks

jj · ‎2011-05-17

Posted on May 17, 2011 at 12:48

Suggest that you first configure PA8 as GPIO and toggle. Armed with that success I suspect that you have missed the set-up/enable of some clock.

Look carefully @ the newest TIM1 examples - most I've tried have worked.

Check that you have newest version of Keil & that it ''plays'' nicely w/ your code library. Good luck.

cpinkstone · ‎2011-05-17

Posted on May 17, 2011 at 12:48

jj,

It was the TIM1 clock enable I'd forgotten!

Cheers. :)

ozenozkaya · ‎2011-05-17

Posted on May 17, 2011 at 12:48

i am trying to use TIM3 Channel 1 as PWM from PC6 as AF; but the brigthness doesnt change. what am i doing wrong?? pls help...

here is the code:

RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM3 , ENABLE);

RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);

GPIO_InitTypeDef GPIO_InitStructure;

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

TIM_OCInitTypeDef TIM_OCInitStructure;

//this pin functions as AF; when remapping

GPIO_PinRemapConfig(GPIO_FullRemap_TIM3, ENABLE);

/*GPIOC Configuration: TIM3 channel 1 */

/* make sure that C port is opened in RCC*/

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_Init(GPIOC, &GPIO_InitStructure);

TIM_Cmd(TIM3, DISABLE);

TIM_ARRPreloadConfig(TIM3, ENABLE);

/* Time base configuration */

TIM_TimeBaseStructure.TIM_Period = 999;

TIM_TimeBaseStructure.TIM_Prescaler = 0;

TIM_TimeBaseStructure.TIM_ClockDivision = 0;

TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

/* PWM1 Mode configuration: Channel1 */

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;

TIM_OCInitStructure.TIM_Channel = TIM_Channel_1;

TIM_OCInitStructure.TIM_Pulse = 500;

TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

TIM_OCInit(TIM3, &TIM_OCInitStructure);

TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);

TIM_ARRPreloadConfig(TIM3, ENABLE);

/* TIM3 enable counter */

TIM_Cmd(TIM3, ENABLE);

TIM_SetCompare1(TIM3,0x10);