/******************** (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 "sys.h"

#include "uart.h"

#include "systim3.h"

/* Private typedef -----------------------------------------------------------*/

/* Private define ------------------------------------------------------------*/

#define ENCODER_TIMER                TIM3  // Encoder unit connected to TIM3

#define ENCODER_PPR           (u16)(900)   // 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)(1000/(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_IPU;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* Enable the TIM3 Update Interrupt */

  NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;

  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_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

  ENCODER_TIMER->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  {

    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 +