/******************** (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 "led.h"
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define ENCODER_TIMER TIM3 // Encoder unit connected to TIM3
#define ENCODER_PPR (u16)(360) // 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 ---------------------------------------------------------*/
s16 hPrevious_angle, hSpeed_Buffer[SPEED_BUFFER_SIZE], hRot_Speed;
u8 bSpeed_Buffer_Index = 0;
volatile u16
hEncoder_Timer_Overflow;
bool bIs_First_Measurement = TRUE;
s16 hSpeed;
u16 hValue;
/*******************************************************************************
* 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; //tck_tim
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) //bIs_First_Measurement=TURE
{
// 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;
}
/*判断正反转*/
if ( (ENCODER_TIMER->CR1 & TIM_CounterMode_Down) == TIM_CounterMode_Down)
{// encoder timer down-counting 反
wDelta_angle = (s32)(hCurrent_angle_sample_one - hPrevious_angle -
(hEnc_Timer_Overflow_sample_one) * (4*ENCODER_PPR));
}
else
{//encoder timer up-counting 正
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) //8次平均
{
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 : TIM3_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++;
}
}
ST给的程序，中间有一些别人写进去的程序，它的计算平均速度ENC_Calc_Average_Speed()这个函数我不是很懂，什么意思。什么思想。 |
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