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 analog.c

 * @brief Analog input and output

 *

 * Contains functions for manipulating the ADC on the Dragonfly board.

 * 

 * @author Colony Project, CMU Robotics Club

 * code mostly taken from fwr analog file (author: Tom Lauwers)

 **/

#include <util/delay.h>

#include <avr/interrupt.h>

#include "analog.h"

// Internal Function Prototypes

void set_adc_mux(int which);

/**

 * @defgroup analog Analog

 * Functions for manipulation the ADC on the dragonfly board.

 * All definitions may be found in analog.h.

 *

 * @{

 **/

int adc_loop_running;

int adc_current_port;

/**

 * Initializes the ADC.

 * Call analog_init before reading from the analog ports.

 *

 * @see analog8, analog10

 **/

void analog_init(void)

{

        // ADMUX register

        // Bit 7,6 - Set voltage reference to AVcc (0b01)

        // Bit 5 - ADLAR not set to simplify moving from register

        // Bit 4 - X

        // Bit 3:0 - Sets the current channel

        // Initializes to read from AN1 first (AN0 is reservered for the BOM)

        ADMUX = ~_BV(REFS1) | _BV(REFS0) | ~_BV(ADLAR) | _BV(MUX0);

        // ADC Status Register A

        // Bit 7 - ADEN is set (enables analog)

        // Bit 6 - Start conversion bit is set (must be done once for free-running mode)

        // Bit 5 - Enable Auto Trigger (for free running mode) NOT DOING THIS RIGHT NOW

        // Bit 4 - ADC interrupt flag, 0

        // Bit 3 - Enable ADC Interrupt (required to run free-running mode)

        // Bits 2-0 - Set to create a clock divisor of 128, to make ADC clock = 8,000,000/64 = 125kHz

        ADCSRA = _BV(ADEN) | _BV(ADSC) | _BV(ADIE) | _BV(ADPS2) | _BV(ADPS1) | ~_BV(ADPS0);

        // Set external mux lines to outputs

        DDRG |= 0x1C;

        set_adc_mux(0x07);

        adc_loop_running = 1;

        adc_current_port = AN1;

}        

unsigned int analog_get8(int which) {

        return an_val[which - 1].adc8;

}

unsigned int analog_get10(int which) {

        return an_val[which - 1].adc10;

}

/**

 * Reads an eight bit number from an analog port.

 * analog_init must be called before using this function.

 * 

 * @param which the analog port to read from. One of

 * the constants AN0 - AN7.

 *

 * @return the eight bit input to the specified port

 *

 * @see analog_init, analog10

 **/

unsigned int analog8(int which)

{

        // Let any previous conversion finish

        while (ADCSRA & _BV(ADSC));

        if(which < EXT_MUX)

                ADMUX = 0x40 + which;

        else if(which == EXT_MUX)

                return 0;

        else

        {

                ADMUX = 0x40 + EXT_MUX;

                set_adc_mux(which - 8);

        }

        // Start the conversion

        ADCSRA |= _BV(ADSC);

        // Wait for the conversion to finish

        while (ADCSRA & _BV(ADSC)) ;

        return ADCL; //since we left aligned the data, ADCH is the 8 MSB.

}

/**

 * Reads a ten bit number from the specified port.

 * analog_init must be called before using this function.

 *

 * @param which the analog port to read from. Typically

 * a constant, one of AN0 - AN7.

 *

 * @return the ten bit number input to the specified port

 * 

 * @see analog_init, analog8

 **/

unsigned int analog10(int which)

{

        // Let any previous conversion finish

        while (ADCSRA & _BV(ADSC));

        if(which < EXT_MUX)

                ADMUX = 0x40 + which;

        else if(which == EXT_MUX)

                return 0;

        else

        {

                ADMUX = 0x40 + EXT_MUX;

                set_adc_mux(which - 8);

        }

        // Start the conversion

        ADCSRA |= _BV(ADSC);

        // Wait for the conversion to finish

        while (ADCSRA & _BV(ADSC)) ;

        return ((ADCH << 8) | ADCL);

}

/**

 * Returns the current position of the wheel, as an integer

 * in the range 0 - 255.

 * analog_init must be called before using this function.

 *

 * @return the orientation of the wheel, as an integer in

 * the range 0 - 255.

 *

 * @see analog_init

 **/

int wheel(void)

{

        return analog_get8(WHEEL_PORT);

}

/**@}**/ //end defgroup

void set_adc_mux(int which)

{

  // FIX THIS IN NEXT REVISION

  // ADDR2 ADDR1 ADDR0

  // G2.G4.G3 set mux to port 0-7 via binary selection

  // math would be much cleaner if it was G4.G3.G2

  // mask so only proper bits are possible.  

  PORTG = (PORTG & 0xE3) | ((which & 0x03) << 3) | (which & 0x04);

}

ISR(ANALOG_COMP_vect) {

        //Only perform this if we are running the loop

        if (!adc_loop_running)

                return;

        an_val[adc_current_port - 1].adc10 = (ADCH << 8) | ADCL;

        //Increment current sensor, wrap around if needed

        if (adc_current_port == AN10) {

                adc_current_port = AN1;

                ADMUX = 0x40 + adc_current_port;

        } else {

                adc_current_port++;

                if(adc_current_port < EXT_MUX) {

                        ADMUX = 0x40 + adc_current_port;

                } else {

                        ADMUX = 0x40 + EXT_MUX;

                        set_adc_mux(adc_current_port - 8);

                }

        }

        ADCSRA |= _BV(ADSC);

}