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Problem with Encoder Interface on STM32F429 Discovery board

Question asked by quang_phu.pham on Oct 1, 2014
Latest reply on Oct 2, 2014 by quang_phu.pham
Hi everyone,
I want to use my encoder with 32bit general purpose timer TIM2 on my STM32F429 Discovery board. I've connected pin PA0 ( TIM2_CH1) and pin PA1 ( TIM2_CH2) to my encoder, but it didn't work. The encoder count value returned only 0 and 1. Then I changed pin PA1 to PB3 ( TIM2_CH2), and it works normally. I've tested on my friend's STM32F4 Discovery board, it also works normally when I connected PA0 and PA1 to my encoder. But I don't know why it doesn't work with my board.
Here's my code:
void RCC_Config()
{
   // Enable GPIO clock
   RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA|RCC_AHB1Periph_GPIOB,ENABLE);
   // Enable SYS clock
   //RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG,ENABLE);
   //Enable TIM
   RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);
}

void GPIO_Config()
{
   GPIO_InitTypeDef GPIO_InitStructure;
  
   //Encoder chanel
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
  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_NOPULL ;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
   
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
  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_NOPULL ;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
   
   //Connect Timer Pins to AF Pins
   GPIO_PinAFConfig(GPIOA,GPIO_PinSource1,GPIO_AF_TIM2);
   GPIO_PinAFConfig(GPIOA,GPIO_PinSource0,GPIO_AF_TIM2);
}

void Encoder_Config()
{
   TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
 
  TIM_TimeBaseStructure.TIM_Prescaler = 0;
  TIM_TimeBaseStructure.TIM_Period = 0xFFFFFFFF;
  TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
   
   TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
   TIM_ARRPreloadConfig(TIM2, ENABLE);
   TIM_SetAutoreload(TIM2,0xFFFFFFFF);
   
   //Debounce filter
//   TIM_ICInitStruct.TIM_Channel=TIM_Channel_1|TIM_Channel_2;
//   TIM_ICInitStruct.TIM_ICFilter=0x3;
//   TIM_ICInitStruct.TIM_ICSelection=TIM_ICSelection_DirectTI;
//   TIM_ICInit(TIM2, &TIM_ICInitStruct);
   
   // set them up as encoder inputs
  TIM_EncoderInterfaceConfig (TIM2, TIM_EncoderMode_TI12, TIM_ICPolarity_Rising, TIM_ICPolarity_Rising);
   // turn on the timer/counters
   TIM_ClearFlag(TIM2,TIM_FLAG_Update);
   TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
   TIM_SetCounter(TIM2,0);
  TIM_Cmd (TIM2, ENABLE);
}

  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4);
  NVIC_Structure.NVIC_IRQChannel = TIM2_IRQn;
  NVIC_Structure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_Structure.NVIC_IRQChannelSubPriority = 0;
  NVIC_Structure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_Structure);
}
void TIM2_IRQHandler(void)
{
  if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET)
  {
      if((TIM2->CR1)&0x10)  // true = giam
         NumEncoder -= 0xFFFFFFFF;
      else
         NumEncoder += 0xFFFFFFFF;  
   
      TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
  }
}

Can anyone help me? I would appreciate any help in determining what my errors are.  Thank you! And sorry for my bad English.

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