stm32f10x_encoder.c

STM32利用正交编码器实现电机的控制

/******************** (C) COPYRIGHT 2007 STMicroelectronics ********************
* File Name          : stm32f10x_encoder.c 
* Author             : IMS Systems Lab  
* Date First Issued  : 21/11/07
* Description        : This file contains the software implementation for the
*                      encoder unit
********************************************************************************
* History:
* 21/11/07 v1.0
********************************************************************************
* THE PRESENT SOFTWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
* WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE TIME.
* AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY DIRECT,
* INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING FROM THE
* CONTENT OF SUCH SOFTWARE AND/OR THE USE MADE BY CUSTOMERS OF THE CODING
* INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
*******************************************************************************/
/* Includes ------------------------------------------------------------------*/
#include "stm32f10x_lib.h"
#include "stm32f10x_encoder.h"
#include "lcd.h"

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define ENCODER_TIMER   TIM3  // Encoder unit connected to TIM3
#define ENCODER_PPR           (u16)(400)   // number of pulses per revolution
#define SPEED_BUFFER_SIZE 8

#define COUNTER_RESET   (u16)0
#define ICx_FILTER      (u8) 6 // 6<-> 670nsec

#define TIMx_PRE_EMPTION_PRIORITY 1
#define TIMx_SUB_PRIORITY 0

#define SPEED_SAMPLING_FREQ (u16)(2000/(SPEED_SAMPLING_TIME+1))

/* Private functions ---------------------------------------------------------*/
s16 ENC_Calc_Rot_Speed(void);

/* Private variables ---------------------------------------------------------*/
static s16 hPrevious_angle, hSpeed_Buffer[SPEED_BUFFER_SIZE], hRot_Speed;
static u8 bSpeed_Buffer_Index = 0;
static volatile u16 hEncoder_Timer_Overflow; 
static bool bIs_First_Measurement = TRUE;

/*******************************************************************************
* Function Name  : ENC_Init
* Description    : General Purpose Timer x set-up for encoder speed/position 
*                  sensors
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void ENC_Init(void)
{
  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
  TIM_ICInitTypeDef TIM_ICInitStructure;
  
/* Encoder unit connected to TIM3, 4X mode */    
  GPIO_InitTypeDef GPIO_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;
  
  /* TIM3 clock source enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
  /* Enable GPIOA, clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
  
  GPIO_StructInit(&GPIO_InitStructure);
  /* Configure PA.06,07 as encoder input */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
  
  /* Enable the TIM3 Update Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQChannel;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = TIMx_PRE_EMPTION_PRIORITY;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = TIMx_SUB_PRIORITY;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  /* Timer configuration in Encoder mode */
  TIM_DeInit(ENCODER_TIMER);
  TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
  
  TIM_TimeBaseStructure.TIM_Prescaler = 0x0;  // No prescaling 
  TIM_TimeBaseStructure.TIM_Period = (4*ENCODER_PPR)-1;  
  TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;   
  TIM_TimeBaseInit(ENCODER_TIMER, &TIM_TimeBaseStructure);
 
  TIM_EncoderInterfaceConfig(ENCODER_TIMER, TIM_EncoderMode_TI12, 
                             TIM_ICPolarity_Rising, TIM_ICPolarity_Rising);
  TIM_ICStructInit(&TIM_ICInitStructure);
  TIM_ICInitStructure.TIM_ICFilter = ICx_FILTER;
  TIM_ICInit(ENCODER_TIMER, &TIM_ICInitStructure);
  
 // Clear all pending interrupts
  TIM_ClearFlag(ENCODER_TIMER, TIM_FLAG_Update);
  TIM_ITConfig(ENCODER_TIMER, TIM_IT_Update, ENABLE);
  //Reset counter
  TIM2->CNT = COUNTER_RESET;
  
  ENC_Clear_Speed_Buffer();
  
  TIM_Cmd(ENCODER_TIMER, ENABLE);  
}

/*******************************************************************************
* Function Name  : ENC_Get_Electrical_Angle
* Description    : Returns the absolute electrical Rotor angle 
* Input          : None
* Output         : None
* Return         : Rotor electrical angle: 0 -> 0 degrees, 
*                                          S16_MAX-> 180 degrees, 
*                                          S16_MIN-> -180 degrees                  
*******************************************************************************/
s16 ENC_Get_Electrical_Angle(void)
{
  s32 temp;
  
  temp = (s32)(TIM_GetCounter(ENCODER_TIMER)) * (s32)(U32_MAX / (4*ENCODER_PPR)); 
  return((s16)(temp/65536)); // s16 result
}

/*******************************************************************************
* Function Name  : ENC_Clear_Speed_Buffer
* Description    : Clear speed buffer used for average speed calculation  
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void ENC_Clear_Speed_Buffer(void)
{   
  u32 i;

  for (i=0;i<SPEED_BUFFER_SIZE;i++)
  {
    hSpeed_Buffer[i] = 0;
  }
  bIs_First_Measurement = TRUE;
}

/*******************************************************************************
* Function Name  : ENC_Calc_Rot_Speed
* Description    : Compute return latest speed measurement 
* Input          : None
* Output         : s16
* Return         : Return the speed in 0.1 Hz resolution.                    
*******************************************************************************/
s16 ENC_Calc_Rot_Speed(void)
{   
  s32 wDelta_angle;
  u16 hEnc_Timer_Overflow_sample_one, hEnc_Timer_Overflow_sample_two;
  u16 hCurrent_angle_sample_one, hCurrent_angle_sample_two;
  signed long long temp;
  s16 haux;
  
  if (!bIs_First_Measurement)
  {
    // 1st reading of overflow counter    
    hEnc_Timer_Overflow_sample_one = hEncoder_Timer_Overflow; 
    // 1st reading of encoder timer counter
    hCurrent_angle_sample_one = ENCODER_TIMER->CNT;
    // 2nd reading of overflow counter
    hEnc_Timer_Overflow_sample_two = hEncoder_Timer_Overflow;  
    // 2nd reading of encoder timer counter
    hCurrent_angle_sample_two = ENCODER_TIMER->CNT;      

    // Reset hEncoder_Timer_Overflow and read the counter value for the next
    // measurement
    hEncoder_Timer_Overflow = 0;
    haux = ENCODER_TIMER->CNT;   
    
    if (hEncoder_Timer_Overflow != 0) 
    {
      haux = ENCODER_TIMER->CNT; 
      hEncoder_Timer_Overflow = 0;            
    }
     
    if (hEnc_Timer_Overflow_sample_one != hEnc_Timer_Overflow_sample_two)
    { //Compare sample 1 & 2 and check if an overflow has been generated right 
      //after the reading of encoder timer. If yes, copy sample 2 result in 
      //sample 1 for next process 
      hCurrent_angle_sample_one = hCurrent_angle_sample_two;
      hEnc_Timer_Overflow_sample_one = hEnc_Timer_Overflow_sample_two;
    }
    
    if ( (ENCODER_TIMER->CR1 & TIM_CounterMode_Down) == TIM_CounterMode_Down)  
    {// encoder timer down-counting
      wDelta_angle = (s32)(hCurrent_angle_sample_one - hPrevious_angle - 
                    (hEnc_Timer_Overflow_sample_one) * (4*ENCODER_PPR));
    }
    else  
    {//encoder timer up-counting
      wDelta_angle = (s32)(hCurrent_angle_sample_one - hPrevious_angle + 
                    (hEnc_Timer_Overflow_sample_one) * (4*ENCODER_PPR));
    }
    
    // speed computation as delta angle * 1/(speed sempling time)
    temp = (signed long long)(wDelta_angle * SPEED_SAMPLING_FREQ);
    temp *= 10;  // 0.1 Hz resolution
    temp /= (4*ENCODER_PPR);
        
  } //is first measurement, discard it
  else
  {
    bIs_First_Measurement = FALSE;
    temp = 0;
    hEncoder_Timer_Overflow = 0;
    haux = ENCODER_TIMER->CNT;       
    // Check if Encoder_Timer_Overflow is still zero. In case an overflow IT 
    // occured it resets overflow counter and wPWM_Counter_Angular_Velocity
    if (hEncoder_Timer_Overflow != 0) 
    {
      haux = ENCODER_TIMER->CNT; 
      hEncoder_Timer_Overflow = 0;            
    }
  }
  
  hPrevious_angle = haux;  
 
  return((s16) temp);
}

/*******************************************************************************
* Function Name  : ENC_Calc_Average_Speed
* Description    : Compute smoothed motor speed based on last SPEED_BUFFER_SIZE
                   informations and store it variable  
* Input          : None
* Output         : s16
* Return         : Return rotor speed in 0.1 Hz resolution. This routine 
                   will return the average mechanical speed of the motor.
*******************************************************************************/
void ENC_Calc_Average_Speed(void)
{   
  s32 wtemp;
  u32 i;
  
  wtemp = ENC_Calc_Rot_Speed();
        
/* Compute the average of the read speeds */  
  hSpeed_Buffer[bSpeed_Buffer_Index] = (s16)wtemp;
  bSpeed_Buffer_Index++;
  
  if (bSpeed_Buffer_Index == SPEED_BUFFER_SIZE) 
  {
    bSpeed_Buffer_Index = 0;
  }

  wtemp=0;

  for (i=0;i<SPEED_BUFFER_SIZE;i++)
  {
    wtemp += hSpeed_Buffer[i];
  }
  wtemp /= SPEED_BUFFER_SIZE;
  
  hRot_Speed = ((s16)(wtemp));
}

/*******************************************************************************
* Function Name  : LCD_Display
* Description    : This function handles the display of timer counter, theta and
                    electronical frequency:
                    theta --- resolution: 1 degree;
                    electronical frequency --- resolution: 0.1Hz.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void LCD_Display(DisplayType DisplayStatus)
{
  u16 hValue;
  s16 Theta;
  s16 hSpeed;
  char *pstr;
  
  switch (DisplayStatus)
  {
    case DISPLAY_TIMCNT: 
      hValue = TIM_GetCounter(ENCODER_TIMER);
      write_string(int2char(hValue));      
    break;
    
    case DISPLAY_THETA:      
      Theta = ENC_Get_Electrical_Angle()*360/U16_MAX;
      if (Theta < 0) 
      {
        hValue = (u16)(-Theta);
        pstr = int2char(hValue);
        *pstr = '-';
      }
      else
      {
        hValue = (u16)Theta;
        pstr = int2char(hValue);
        if (hValue != 0) *pstr = '+';  
      }
      write_string(pstr);
    break;
    
    default:
      hSpeed = hRot_Speed;
      if (hSpeed < 0) 
      {
        hValue = (u16)(-hSpeed);
        pstr = int2char(hValue);
        *pstr = '-';
      }
      else
      {
        hValue = (u16)hSpeed;
        pstr = int2char(hValue);
        if (hValue != 0) *pstr = '+';  
      }
      write_string(pstr);
    break;
  }
}

/*******************************************************************************
* Function Name  : TIM2_IRQHandler
* Description    : This function handles TIMx Update interrupt request.
                   Encoder unit connected to TIM2
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void TIM3_IRQHandler(void)
{  
  /* Clear the interrupt pending flag */
  TIM_ClearFlag(ENCODER_TIMER, TIM_FLAG_Update);
  
  if (hEncoder_Timer_Overflow != U16_MAX)  
  {
   hEncoder_Timer_Overflow++;
  }
}

/******************* (C) COPYRIGHT 2007 STMicroelectronics *****END OF FILE****/