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I need to PWM my LED on STM32F3 Discovery which is on PE8. I have found code which is using PWM on PA8 and PC8 (one using TIM1) but unfortunately I can't change it to PE8.

How to do it? Or maybe you have better code to enable PWM using TIM1?

Original code:

#include "main.h"                                                                                               //main library to include for device drivers, peripheral drivers, etc.
void RCC_Configuration(void);
void GPIO_Configuration(void);

// Unused global variables that have to be included to ensure correct compiling */
// ###### DO NOT CHANGE ######
// ===============================================================================
__IO uint32_t TimingDelay = 0;                                                                  //used with the Delay function
__IO uint8_t DataReady = 0;
__IO uint32_t USBConnectTimeOut = 100;
__IO uint32_t UserButtonPressed = 0;
__IO uint8_t PrevXferComplete = 1;
// ===============================================================================



int main(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_OCInitTypeDef TIM_OCInitStructure;


    RCC_Configuration();
    GPIO_Configuration();



    TIM_TimeBaseStructure.TIM_Period = 600;
    TIM_TimeBaseStructure.TIM_Prescaler = 6000-1;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
    TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);

    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 600/1.2;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

    TIM_OC3Init(TIM3, &TIM_OCInitStructure);
    TIM_OC1Init(TIM1, &TIM_OCInitStructure);

    TIM_Cmd(TIM3, ENABLE);
    TIM_Cmd(TIM1, ENABLE);

    TIM_CtrlPWMOutputs(TIM1, ENABLE); 

    while (1);

}

void RCC_Configuration(void)
{
   RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA,ENABLE);
   RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOC,ENABLE);
   RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
   RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
}

void GPIO_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

   GPIOA->AFR[1] |= 6; // AF6
   GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_8 ;
   GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF;
   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
   GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
   GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_UP;

   GPIO_Init(GPIOA, &GPIO_InitStructure);

   GPIOC->AFR[1] |= 2; // AF2
   GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_8;
   GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF;
   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
   GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
   GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_UP;
   GPIOC->AFR[1] |= 2;

   GPIO_Init(GPIOC, &GPIO_InitStructure);
}


// Function to insert a timing delay of nTime
// ###### DO NOT CHANGE ######
void Delay(__IO uint32_t nTime)
{
  TimingDelay = nTime;

  while(TimingDelay != 0);
}

// Function to Decrement the TimingDelay variable.
// ###### DO NOT CHANGE ######
void TimingDelay_Decrement(void)
{
  if (TimingDelay != 0x00)
  { 
    TimingDelay--;
  }
}

// Unused functions that have to be included to ensure correct compiling
// ###### DO NOT CHANGE ######
// =======================================================================
uint32_t L3GD20_TIMEOUT_UserCallback(void)
{
  return 0;
}

uint32_t LSM303DLHC_TIMEOUT_UserCallback(void)
{
  return 0;
}
// =======================================================================

Edited part:

void RCC_Configuration(void)
{
   RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA,ENABLE);
   RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOE,ENABLE);
   RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
   RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
}

void GPIO_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

   GPIOA->AFR[1] |= 6; // AF6
   GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_8 ;
   GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF;
   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
   GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
   GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_UP;

   GPIO_Init(GPIOA, &GPIO_InitStructure);

   GPIOE->AFR[1] |= 2; // AF2
   GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_8;
   GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF;
   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
   GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
   GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_UP;
   GPIOE->AFR[1] |= 2;

   GPIO_Init(GPIOE, &GPIO_InitStructure);
}
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  • \$\begingroup\$ I'm not clear on what the problem is. TIM1 can have it's inverted channel 1 output compare mapped to PE8. If you don't like / can't understand ST's awful HAL libraries then just access the RCC, TIM1 and GPIOE peripheral registers directly. It should take less than 20 lines of C to get it working. \$\endgroup\$
    – markt
    Mar 7, 2015 at 3:57

1 Answer 1

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The problem was with alternating function. I had to find a table and change it to proper one for port E :)

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