429I-DISCO PWM output

yoshi · ‎2014-12-03

Posted on December 04, 2014 at 05:01

Hi,

I'd like to output 30kHz PWM from PA5, but following code won't work.

What is wrong with this code?

#include ''stm32f4xx.h''

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

TIM_OCInitTypeDef TIM_OCInitStructure;

uint16_t CCR1_Val = 350;

uint16_t PrescalerValue = 0;

void TIM_Config(void);

int main(void)

{

GPIO_InitTypeDef GPIO_InitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

/* GPIOA Configuration: TIM2 CH1 (PA5) */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;

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_UP ;

GPIO_Init(GPIOA, &GPIO_InitStructure);

GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_TIM2);

RCC_TIMCLKPresConfig(RCC_TIMPrescActivated);

PrescalerValue = (uint16_t) (SystemCoreClock / 21000000) - 1;

TIM_TimeBaseStructure.TIM_Period = 699;

TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;

TIM_TimeBaseStructure.TIM_ClockDivision = 0;

TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;

TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;

TIM_OCInitStructure.TIM_Pulse = CCR1_Val;

TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

TIM_OC1Init(TIM2, &TIM_OCInitStructure);

TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Enable);

TIM_ARRPreloadConfig(TIM2, ENABLE);

TIM_Cmd(TIM2, ENABLE);

while (1) {}

} This code was modified from Peripheral_Examples on stsw-stm32138,

If the setting is original TIM4 CH1 PD12, then it was working well.

tyro

yoshi · ‎2014-12-04

Posted on December 04, 2014 at 09:26

My god, I found that I always checked

PA7

instead of

PA5.

I must return to my office for signal check

because

there is oscilloscope.

429I-DISCO does not print the pin name at one side of P1 and P2,

so I had thought that PA5 must be next to PA4, but it has reverse sequence against an actual pin numbers.

yoshi · ‎2014-12-04

Posted on December 04, 2014 at 10:40

Solved. PWM output from PA5 was working well.

tyro