STM32F107 Quadrature encoder

[JJohn.3]

Hello,

Regarding this post I am able to read my encoder value correctly.

 // STM32 TIM3 Encoder Decoder (PC.06:A PC.07:B) VLDiscovery - [e-mail]
 #include ''stm32F10x.h''
 #include ''STM32vldiscovery.h''
 /**************************************************************************************/
 void RCC_Configuration(void)
 {
 // clock for GPIO and AFIO (for ReMap)
 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC | RCC_APB2Periph_AFIO, ENABLE);
 // clock for TIM3
 RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
 }
 /**************************************************************************************/
 void GPIO_Configuration(void)
 {
 GPIO_InitTypeDef GPIO_InitStructure;
 // PC.06 TIM3_CH1, PC.07 TIM3_CH2
 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
 GPIO_Init(GPIOC, &GPIO_InitStructure);
 GPIO_PinRemapConfig( GPIO_FullRemap_TIM3, ENABLE ); // Map TIM3 to GPIOC
 }
 /**************************************************************************************/
 void TIM3_Configuration(void)
 {
 TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
 TIM_TimeBaseStructure.TIM_Prescaler = 0; 
 TIM_TimeBaseStructure.TIM_Period = 65535; // Maximal
 TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
 TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
 // TIM_EncoderMode_TI1: Counter counts on TI1FP1 edge depending on TI2FP2 level.
 TIM_EncoderInterfaceConfig(TIM3, TIM_EncoderMode_TI1, TIM_ICPolarity_Rising, TIM_ICPolarity_Rising);
 TIM_Cmd(TIM3, ENABLE);
 }
 /**************************************************************************************/
 int main(void)
 {
 RCC_Configuration();
 GPIO_Configuration();
 TIM3_Configuration();
 // TIM3->CNT contains current position
 while(1)
 
{
 Print(TIM3->CNT);
}
 
 
 
 }

My problem appears when I want to know the direction and number of pulse in each direction.

For example if the counter value is zero and I change the encoder position (when the previous value is 0 )and the next value is 65532 I need to know to determine the pulse changes is 2. And if the first value is 0 and the next value is 2 how to determine the pulse and rotation direction. In addition I need to know if the previous value is 65530 and the next value is 2 how to determine the number of pulses and the direction while the value of my timer is between 0 to 65535.

This confused me. I will be grateful if you could help me in this issue.

[TDK]

Save the value periodically and determine the speed by the shortest distance between readings. If the last reading was 65535 and the next is 0, rotation was 1 unit in the positive direction. Calculate both direction and use the one that is shortest.