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stm32F051 discovery Timer1 PWM

tergu
Associate II
Posted on December 17, 2015 at 19:59

Hi,

I am trying to get a PWM Signal out of my discovery board but I must be missing something. I started with a writingthe registers directly, then I tried it with the peripheral library. Ilooked at various examples but I cannot find my problem. The timer is running, I can toggle the pin...Please somebody help me, I am going crazy! Here is the code. Best regards, Christian

#include ''stm32f0xx.h'' 
#include ''stm32f0xx_gpio.h'' 
#include ''stm32f0xx_rcc.h'' 
#include ''stm32f0xx_tim.h'' 
#include ''system_stm32f0xx.h'' 
void
main(
void
) 
{ 
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; 
TIM_OCInitTypeDef TIM_OCInitStructure; 
GPIO_InitTypeDef GPIO_InitStructure; 
uint16_t period; 
uint16_t pulse; 
SystemInit(); 
period = 0xFF; 
pulse = period >> 1; 
/* GPIOA clock enable */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE); 
/* Initialize PA8, Alternative Function, 50Mhz, Output, Push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8; 
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; 
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_Level_3; 
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; 
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP ; 
GPIO_Init(GPIOA, &GPIO_InitStructure); 
GPIO_PinAFConfig(GPIOA, GPIO_PinSource8, GPIO_AF_0); 
/* TIM1 clock enable */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 , ENABLE); 
/* Timer Base configuration */
TIM_TimeBaseStructInit(&TIM_TimeBaseStructure); 
TIM_TimeBaseStructure.TIM_Prescaler = 0; 
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; 
TIM_TimeBaseStructure.TIM_Period = period; 
TIM_TimeBaseStructure.TIM_ClockDivision = 0; 
TIM_TimeBaseStructure.TIM_RepetitionCounter = 0; 
TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure); 
/* Channel 1 output configuration */
TIM_OCStructInit(&TIM_OCInitStructure); 
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; 
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; 
TIM_OCInitStructure.TIM_Pulse = pulse; 
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; 
TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set; 
TIM_OC1Init(TIM1, &TIM_OCInitStructure); 
/* Enable Preload register on CCR1. */
TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Enable); 
/* TIM1 counter enable */
TIM_Cmd(TIM1, ENABLE); 
/* TIM1 Main Output Enable */
TIM_CtrlPWMOutputs(TIM1, ENABLE); 
/* forever... */
while
(1) 
{ 
__asm(
''nop''
); 
} 
} 

2 REPLIES 2
Posted on December 17, 2015 at 23:11

GPIO_PinAFConfig(GPIOA, GPIO_PinSource8, GPIO_AF_2);  http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/DM00039pdf 

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tergu
Associate II
Posted on December 18, 2015 at 08:58

OMG!

Thanks a lot, I must have been blind to not see that.

Best regards,

Christian.