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.

 **/

#include "rangefinder.h"

#include "util.h"

#include "robot_shared.h"

extern RobotShared* shared_state;

/*

        read_distance returns the 8-bit reading from the rangefinder

        parameters:

        range_id - dio pin set as the rangefinder Vout [i.e. RANGE_IN0]

        NOTE:

        The Sharp GD2D02 returns values on a decreasing logrithmic scale.

        So higher values correspond to closer distances.        Use linearize_distance to convert to normal centimeter scale.        Also, when reading distances closer than 8cm, the Sharp GD2D02 will return lower values than the values at 8cm.

        At this point, we are only reading from one rangefinder [RANGE_IN0].

*/

// constants

/* Nasty IR approximation table

         I'm using this for the heck of it.        We can do whatever.

         Note the minimum value is .4V (20), and the maximum is 2.6V (133).

         Gives distance in mm.

         excel formula(valid for inputs 20-133):        ROUND(2353.6*(E2^(-1.1146))*10,0)

         This is only valid for the GP2D12, with objects directly ahead and more than

         10cm from the detector.        See the datasheet for more information.

*/

#define MIN_IR_ADC8 20

#define MAX_IR_ADC8 133

void range_init(void)

{

        /* simulator does not need this */

}

int range_read_distance (int range_id)

{

        int temp=0;

        /* read from array in shared memory, if valid */

        if (range_id > 0 && range_id < 6) {

                temp = (shared_state->ranges).d[range_id];

                if (temp < 0 || temp > 1000)

                        return -1;

                else

                        return temp;

        }

        return -1;

}