#include "main.h"

/*

PA7——TIM3_CH2

PA6——TIM3_CH1

PB7——TIM4_CH2

PB6——TIM4_CH1

*/

int Timer3_Overflow;

int Timer4_Overflow;

void wheel_encoder_configuration(void)

{

GPIO_InitTypeDef ENCODER;

TIM_TimeBaseInitTypeDef TIMER3, TIMER4;

TIM_ICInitTypeDef IC_ENCODER;

NVIC_InitTypeDef nvic;

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA|RCC_AHB1Periph_GPIOB, ENABLE);

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3|RCC_APB1Periph_TIM4, ENABLE);

//PA6、PA7的复用功能一定要分开配置才行

GPIO_PinAFConfig(GPIOA,GPIO_PinSource6, GPIO_AF_TIM3);

GPIO_PinAFConfig(GPIOA,GPIO_PinSource7, GPIO_AF_TIM3);

ENCODER.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;

ENCODER.GPIO_Mode = GPIO_Mode_AF;

ENCODER.GPIO_Speed = GPIO_Speed_100MHz;

ENCODER.GPIO_PuPd = GPIO_PuPd_DOWN;

GPIO_Init(GPIOA, &ENCODER);

GPIO_PinAFConfig(GPIOB,GPIO_PinSource6, GPIO_AF_TIM4);

GPIO_PinAFConfig(GPIOB,GPIO_PinSource7, GPIO_AF_TIM4);

ENCODER.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;

ENCODER.GPIO_Mode = GPIO_Mode_AF;

ENCODER.GPIO_Speed = GPIO_Speed_100MHz;

ENCODER.GPIO_PuPd = GPIO_PuPd_DOWN;

GPIO_Init(GPIOB, &ENCODER);

/***********configure the TIM3**********/

TIMER3.TIM_Prescaler = 0;

TIMER3.TIM_Period = 0xffff;

TIMER3.TIM_ClockDivision = TIM_CKD_DIV1;

TIMER3.TIM_CounterMode = TIM_CounterMode_Up;

TIM_TimeBaseInit(TIM3, &TIMER3);

/***********configure the TIM4***********/

TIMER4.TIM_Prescaler = 0;

TIMER4.TIM_Period = 0xffff;

TIMER4.TIM_ClockDivision = TIM_CKD_DIV1;

TIMER4.TIM_CounterMode = TIM_CounterMode_Up;

TIM_TimeBaseInit(TIM4, &TIMER4);

/**********Set TIM3 and TIM4 to the ecoder mode***************/

TIM_EncoderInterfaceConfig(TIM3, TIM_EncoderMode_TI12, TIM_ICPolarity_Falling, TIM_ICPolarity_Falling);

TIM_EncoderInterfaceConfig(TIM4, TIM_EncoderMode_TI12, TIM_ICPolarity_Falling, TIM_ICPolarity_Falling);

/**********Set TIM3 and TIM4 to the input capture mode***************/

IC_ENCODER.TIM_Channel = TIM_Channel_1;

IC_ENCODER.TIM_ICSelection = TIM_ICSelection_DirectTI;

TIM_ICInit(TIM3, &IC_ENCODER);

IC_ENCODER.TIM_Channel = TIM_Channel_2;

IC_ENCODER.TIM_ICSelection = TIM_ICSelection_DirectTI;

TIM_ICInit(TIM3, &IC_ENCODER);

IC_ENCODER.TIM_Channel = TIM_Channel_1;

IC_ENCODER.TIM_ICSelection = TIM_ICSelection_DirectTI;

TIM_ICInit(TIM4, &IC_ENCODER);

IC_ENCODER.TIM_Channel = TIM_Channel_2;

IC_ENCODER.TIM_ICSelection = TIM_ICSelection_DirectTI;

TIM_ICInit(TIM4, &IC_ENCODER);

/*************Configurate interrupts of TIM3 and TIM4*********/

nvic.NVIC_IRQChannel = TIM3_IRQn;

nvic.NVIC_IRQChannelPreemptionPriority = 2;

nvic.NVIC_IRQChannelSubPriority = 2;

nvic.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&nvic);

nvic.NVIC_IRQChannel = TIM4_IRQn;

nvic.NVIC_IRQChannelPreemptionPriority = 2;

nvic.NVIC_IRQChannelSubPriority = 2;

nvic.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&nvic);

/*Clear the interruput flag and then enable the interrupt*/

TIM_ClearFlag(TIM3, TIM_FLAG_Update);

TIM_ClearFlag(TIM4, TIM_FLAG_Update);

TIM_ITConfig(TIM3, TIM_IT_Update, ENABLE);

TIM_ITConfig(TIM4, TIM_IT_Update, ENABLE);

/*Set TIM3 and TIM4 CNT to 0x7fff*/

TIM_SetCounter(TIM3,0x7fff);

TIM_SetCounter(TIM4,0x7fff);

/*Enable TIM3 and TIM4 */

TIM_Cmd(TIM3, ENABLE);

TIM_Cmd(TIM4, ENABLE);

}

int encoderR_get_cnt(void)

{

/*get the speed of right wheel */

int cnt = 0;

cnt = (TIM3 -> CNT) - 0x7fff;

TIM3 -> CNT = 0x7fff;

return cnt;

}

int encoderL_get_cnt(void)

{

/*get the speed of left wheel*/

int cnt = 0;

cnt = (TIM4 -> CNT) - 0x7fff;

TIM4 -> CNT = 0x7fff;

return cnt;

}

void TIM3_IRQHandler(void)

{

TIM_ClearFlag(TIM3, TIM_FLAG_Update);

if(Timer3_Overflow != 0xffffffff)

{

Timer3_Overflow++;

}

}

void TIM4_IRQHandler(void)

{

TIM_ClearFlag(TIM4, TIM_FLAG_Update);

if(Timer4_Overflow != 0xffffffff)

{

Timer4_Overflow++;

}

}

刚开始在调试的时候遇到了问题，读出来的cnt值只有0,1，-1，而且根本没有什么规律，后来发现是gpio的配置有问题，相应的GPIO口应该配制成GPIO_Mode_AF，而不是GPIO_Mode_IN，而且配置复用功能的时候，GPIO_PinAFConfig（）函数的参数一定要注意，GPIO_PinSource参数只能写一个，不要讲多个GPIO_PinSource与在一起。比如，要配置PA6和PA7，应写成这样：

GPIO_PinAFConfig(GPIOA,GPIO_PinSource6, GPIO_AF_TIM3);

GPIO_PinAFConfig(GPIOA,GPIO_PinSource7, GPIO_AF_TIM3);

而不要写出这样：

GPIO_PinAFConfig(GPIOA,GPIO_PinSource6| GPIO_PinSource7, GPIO_AF_TIM3);

程序中CNT寄存器的初值设置为0X7fff，这样的话无论一开始轮子是正转还是反转，都基本不会溢出，但是为了防止溢出的情况，又在两个定时器的中断函数中对溢出次数进行计数，在后续的应用中就可以结合溢出次数和CNT计数器的值，得到实际的计数值。