Colony

/**

 * Copyright (c) 2007 Colony Project

 *

 * Permission is hereby granted, free of charge, to any person

 * obtaining a copy of this software and associated documentation

 * files (the "Software"), to deal in the Software without

 * restriction, including without limitation the rights to use,

 * copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following

 * conditions:

 *

 * The above copyright notice and this permission notice shall be

 * included in all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES

 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,

 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

 * OTHER DEALINGS IN THE SOFTWARE.

 **/

/**

 * @file encoders.c

 * @brief Implemenation of encoders.

 *

 * Contains implementation of functions controlling and

 * reading from the encoders.

 *

 * @author CMU Robotics Club

 * @bug Not tested.

 */

#include "encoders.h"

#include "spi.h"

#include <dragonfly_lib.h>

#include "ring_buffer.h"

unsigned int left_data_buf;

unsigned int right_data_buf;

char encoder_buf_index;

unsigned int left_data;

unsigned int right_data;

unsigned int left_data_array[BUFFER_SIZE];

unsigned int right_data_array[BUFFER_SIZE];

int left_data_idx;

int right_data_idx;

int left_dx;

int right_dx;

long int timecount;

int left_v;

int right_v;

volatile short int data_ready;

void encoder_recv(char data);

//Helper Function Prototypes

inline void left_data_array_put(unsigned short int value);

inline unsigned int left_data_array_top(void);

inline unsigned int left_data_array_prev(void);

inline unsigned int left_data_array_bottom(void);

inline void right_data_array_put(unsigned short int value);

inline unsigned int right_data_array_top(void);

inline unsigned int right_data_array_prev(void);

inline unsigned int right_data_array_bottom(void);

void encoder_recv_complete(){

          encoder_buf_index = 0;

        data_ready++;

           spi_transfer(5);

}

void encoders_init(void){

        int i;

        data_ready=0;

        spi_init(encoder_recv, encoder_recv_complete);

        encoder_buf_index = 0;

        left_data_buf = 0;

        right_data_buf= 0;

        left_data = -1;

        right_data = -1;

        left_v=0;

        right_v=0;

        //RING_BUFFER_INIT(enc_buffer,BUFFER_SIZE);

        left_data_idx = 0;

        right_data_idx = 0;

        for(i = 0; i < BUFFER_SIZE; i++) {

                left_data_array[i] = 0;

        }

        for(i = 0; i < BUFFER_SIZE; i++) {

                right_data_array[i] = 0;

        }

        spi_transfer(5);

}

int encoder_read(char encoder){

        if(encoder==LEFT) return left_data;

        else if(encoder==RIGHT) return right_data;

        else return -1;

}

int encoder_get_dx(char encoder) {

        if(encoder==LEFT) return left_dx;

        else if(encoder==RIGHT) return right_dx;

        else return -1;

}

void encoder_rst_dx(char encoder) {

        if(encoder==LEFT) left_dx = 0;

        else if(encoder==RIGHT) right_dx = 0;

}

int encoder_get_tc(void) {

        return timecount;

}

void encoder_rst_tc(void) {

        timecount = 0;

}

void encoder_wait(int n){

        while(data_ready<n);

        data_ready=0;

}

//Full reads occur every 40 microseconds. This function should be called

//every 8 microseconds.

void encoder_recv(char data){

        short int dx;

        //Parse the encoder data, comes in over 5 bytes 16 bits per encoder,

        // second is offset by 1 bit.

        switch(encoder_buf_index){

        case 0:

                right_data_buf |= ((short)data)<<8 & 0xff00;

                break;

        case 1:

                right_data_buf |= ((short)data) & 0xff;

                break;

        case 2:

                left_data_buf |= (((short)data) << 9) & (0x7F << 9);

                break;

        case 3:

                left_data_buf |= (((short)data) << 1) & (0xFF<<1);

                break;

        case 4: left_data_buf |= (((short)data)>>7) & 0x1;

        }

        encoder_buf_index = (encoder_buf_index + 1) % 5;

        if(encoder_buf_index==0) {

                /*Error handling for the left encoder*/

                if(!(left_data_buf & OCF))

                        left_data = ENCODER_DATA_NOT_READY;

                if(left_data_buf & (COF | LIN))

                        left_data = ENCODER_MISALIGNED;

                else if((left_data_buf & MagINCn) && (left_data_buf & MagDECn))

                        left_data = ENCODER_MAGNET_FAILURE;

                else left_data = (left_data_buf>>5) & 1023;

                /*Error handling for the right encoder*/

                 if(!(right_data_buf & OCF))

                        right_data = ENCODER_DATA_NOT_READY;

                if(right_data_buf & (COF | LIN))

                        right_data = ENCODER_MISALIGNED;

                else if ((right_data_buf & MagINCn)  && (right_data_buf & MagDECn))

                        right_data = ENCODER_MAGNET_FAILURE;

                else right_data = (right_data_buf>>5) & 1023;

                  left_data_buf = 0;

                right_data_buf = 0;

                /*Note: Above 1023 is invalid data*/

                if(!(left_data > 1023)) {

                        //Reverse the left wheel since encoders are necessarily mounted backwards.

                        left_data = 1023 - left_data;

                        left_data_array_put(left_data);

                        //Adjust left accumulator

                        dx = left_data - left_data_array_prev();

                        //Adjust velocity: save last dx

                        left_v = left_dx;

                        if(left_data_array_prev()==0)  dx=0;

                        if(dx > 512) left_dx += dx - 1023; //Underflow

                        else if(dx < -512) left_dx += dx + 1023; //Overflow

                        else left_dx += dx;

                        //Adjust velocity: update

                        left_v = left_dx - left_v;

                }

                /*Above 1023 is invalid data*/

                if(!(right_data > 1023)) {

                        right_data_array_put(right_data);

                        //Adjust right accumulator

                        dx = right_data - right_data_array_prev();

                        if(right_data_array_prev()==0) dx=0;

                        if(dx > 512) right_dx += dx - 1023; //underflow

                        else if(dx < -512) right_dx += dx + 1023; //overflow

                        else right_dx += dx;

                }

        }

        //Increment timecount accumulator

        timecount++;

}

//Helper Functions

inline void left_data_array_put(unsigned short int value) {

        if(left_data_idx == BUFFER_SIZE-1)

                left_data_idx = 0;

        else

                left_data_idx++;

        left_data_array[left_data_idx] = value;

}

inline unsigned int left_data_array_top(void) {

        return left_data_array[left_data_idx];

}

inline unsigned int left_data_array_prev(void) {

        if(left_data_idx == 0)

                return left_data_array[BUFFER_SIZE-1];

        else

                return left_data_array[left_data_idx - 1];

}

inline unsigned int left_data_array_bottom(void) {

        if(left_data_idx == BUFFER_SIZE-1)

                return left_data_array[0];

        else

                return left_data_array[left_data_idx + 1];

}

inline void right_data_array_put(unsigned short int value) {

        if(right_data_idx == BUFFER_SIZE-1)

                right_data_idx = 0;

        else

                right_data_idx++;

        right_data_array[right_data_idx] = value;

}

inline unsigned int right_data_array_top(void) {

        return right_data_array[right_data_idx];

}

inline unsigned int right_data_array_prev(void) {

        if(right_data_idx == 0)

                return right_data_array[BUFFER_SIZE-1];

        else

                return right_data_array[right_data_idx - 1];

}

inline unsigned int right_data_array_bottom(void) {

        if(right_data_idx == BUFFER_SIZE-1)

                return right_data_array[0];

        else

                return right_data_array[right_data_idx + 1];

}