Question

我正在尝试在STM32F4DISCOVERY板上使用TIM4进行正交编码器输入。这是我的代码：

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);

GPIO_InitTypeDef GPIO_InitStructure;
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_InitStructure.GPIO_Pin = GPIO_Pin_6| GPIO_Pin_7;
GPIO_Init(GPIOB, &GPIO_InitStructure);

GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_TIM4);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_TIM4);

/* Configure the timer */
TIM_EncoderInterfaceConfig(TIM4, TIM_EncoderMode_TI12, TIM_ICPolarity_Rising, TIM_ICPolarity_Rising);

/* TIM4 counter enable */
TIM_Cmd(TIM4, ENABLE);

遗憾的是，当我转动编码器时，TIM4-> CNT计数器不会移动。我与TIM8完美搭配。以下是工作TIM8和不工作TIM4的完整代码： https://gist.github.com/nraynaud/5082298

我手动移动编码器后在gdb中打印rT2（）进行检查。

Answer 1

我使用STM32F407从3个光学编码器读取编码器计数。我正在使用ChibiOS RTOS，因此定时器结构与ST外设库定时器结构略有不同，但信息基本相同。以下是我如何配置实际定时器的寄存器：

stm32_tim_t * encoderTimers[3] = {STM32_TIM8, STM32_TIM3, STM32_TIM4};
for (auto timer : encoderTimers) {
  timer->SMCR = 3;          // Encoder mode 3
  timer->CCER = 0;          // rising edge polarity
  timer->ARR = 0xFFFF;      // count from 0-ARR or ARR-0
  timer->CCMR1 = 0xC1C1;    // f_DTS/16, N=8, IC1->TI1, IC2->TI2
  timer->CNT = 0;           // Initialize counter
  timer->EGR = 1;           // Generate an update event
  timer->CR1 = 1;           // Enable the counter
}

另外，请确保在RCC的APB1或APB2寄存器中启用定时器外设。类似的东西：

RCC->APB1ENR |= ((1 <<  2)  // TIM4  --  Front wheel angle measurement
             |   (1 <<  1));// TIM3  --  Steer angle measurement

最后，您需要确保正确配置GPIO设置。这意味着将GPIO配置为备用功能。

Answer 2

除非使用外部电阻，否则可能需要使用上拉输入或为编码器供电。我通常将编码器连接到地，并使用内部上拉来设置空闲状态。

Answer 3

带标准驱动程序的编码器

#include "mbed.h"
#include "stm32f4xx.h"
#include "stm32f4xx_hal_tim_ex.h"

TIM_HandleTypeDef timer;
TIM_Encoder_InitTypeDef encoder;

//direction to PA_9 -- step pulse to PA_8

int main(){
     GPIO_InitTypeDef GPIO_InitStruct;
        __TIM1_CLK_ENABLE();
        __GPIOA_CLK_ENABLE();
        GPIO_InitStruct.Pin = GPIO_PIN_8 | GPIO_PIN_9;
        GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
        GPIO_InitStruct.Pull = GPIO_PULLDOWN;
        GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
        GPIO_InitStruct.Alternate = GPIO_AF1_TIM1;
        HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

    timer.Instance = TIM1;
    timer.Init.Period = 0xffff;
    timer.Init.Prescaler = 0;
    timer.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
    timer.Init.CounterMode = TIM_COUNTERMODE_UP;

    encoder.EncoderMode = TIM_ENCODERMODE_TI12; 
    encoder.IC1Filter = 0x0f;
    encoder.IC1Polarity = TIM_INPUTCHANNELPOLARITY_RISING; 
    encoder.IC1Prescaler = TIM_ICPSC_DIV4;
    encoder.IC1Selection = TIM_ICSELECTION_DIRECTTI;

    encoder.IC2Filter = 0x0f;
    encoder.IC2Polarity = TIM_INPUTCHANNELPOLARITY_FALLING;    
    encoder.IC2Prescaler = TIM_ICPSC_DIV4;
    encoder.IC2Selection = TIM_ICSELECTION_DIRECTTI;

    HAL_TIM_Encoder_Init(&timer, &encoder);
    HAL_TIM_Encoder_Start(&timer,TIM_CHANNEL_1);   


    TIM1->EGR = 1;           // Generate an update event
    TIM1->CR1 = 1;           // Enable the counter


 while (1) {
        int16_t count1; 
        count1=TIM1->CNT; 

        printf("%d\r\n", count1);
        wait(1.0);

 };
}

TIM4上的STM32旋转编码器配置

3 个答案: