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.

 * It operates by running throug all available analog ports (set by AN_MAX,

 * see analog.h for details on that constant). It performs a conversion for

 * each port and stores the 8bit and 10bit value. It then increments the 

 * port that it is looking at and then procedes to do another read.

 *

 * analog8 and analog10 are changed to use the lookup table. To use the

 * historic functions, use analog_get8 and analog_get10. If you do use those,

 * it is advised to turn off the loop by calling analog_stop_loop and restarting

 * the loop when done with analog_start_loop. This is especially important if you

 * are planning on doing a series of analog_getX reads.

 *

 * This function pretty intensive on the interrupts as it will be called quite

 * often. Plan ahead for this.

 * 

 * @author Colony Project, CMU Robotics Club, Kevin Woo

 * Originally based on fwr code by Tom Lauwers

 **/

#include <util/delay.h>

#include <avr/interrupt.h>

#include "analog.h"

#include "serial.h"

// Internal Function Prototypes

void set_adc_mux(int which);

/** @brief Struct to hold the value of a particular analog port */

typedef struct {

        uint8_t adc8;

        uint16_t adc10;

} adc_t;

/**

 * @defgroup analog Analog

 * Functions for manipulation the ADC on the dragonfly board.

 * All definitions may be found in analog.h.

 *

 * @{

 **/

int adc_loop_running = 0;

int adc_current_port = 0;

adc_t an_val[11];

/**

 * Initializes the ADC.

 * Call analog_init before reading from the analog ports.

 *

 * @see analog8, analog10, analog_get8, analog_get10, analog_start_loop

 *      analog_stop_loop

 **/

void analog_init(int start_conversion)

{

    //Initialize the array to 0

        for (int i = 0; i < (AN_MAX + 1); i++) {

                an_val[i].adc10 = 0;

                an_val[i].adc8 = 0;

        }

        // ADMUX register

        // The following bits are set

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

        // Bit 5 - ADLAR 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 = 0;

        ADMUX |= ADMUX_OPT | _BV(MUX0);

        // ADC Status Register A

        // The following bits are set

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

        // 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 = 0;

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

        // Set external mux lines to outputs

        DDRG |= 0x1C;

        // Set up first port for conversions

        set_adc_mux(0x00);

        adc_current_port = AN1;

        // Start the conversion if requested

        if (start_conversion)

                analog_start_loop();

        else

                analog_stop_loop();

}        

/**

 * Reads an analog value from the look-up table. Values are not

 * good unless the analog loop is running.

 *

 * @param which is the analog port you wish to read.

 *

 * @return returns an 8 bit value which represents the analog value

 *

 * @see analog8, analog_start_loop, analog_stop_loop, analog_init

 **/

unsigned int analog_get8(int which) {

        if (which == BOM_PORT) {

                return 0;

        } else {

                return an_val[which - 1].adc8;

        }

}

/**

 * Reads an analog value from the look-up table. Values are not

 * good unless the analog loop is running.

 *

 * @param which is the analog port you wish to read.

 *

 * @return returns an 10 bit value which represents the analog value

 *

 * @see analog8, analog_start_loop, analog_stop_loop, analog_init

 **/

unsigned int analog_get10(int which) {

        if (which == BOM_PORT) {

                return 0;

        } else {

                return an_val[which - 1].adc10;

        }

}

/**

 * Starts the analog loop to put values into the lookup table. Need

 * to have the loop running before analog_get8 and analog_get10 are

 * valid.

 *

 * @see analog_stop_loop, analog_init, analog_get8, analog_get10

 **/

void analog_start_loop(void) {

        //Start the conversion

        ADCSRA |= _BV(ADSC);

        adc_loop_running = 0x1;

}

/**

 * Starts the analog loop to put values into the lookup table. You

 * should disable to loop to use analog8 and analog10 reliably.

 *

 * @see analog_stop_loop, analog_init, analog8, analog10

 **/

void analog_stop_loop(void) {

        //Stop the conversion

        adc_loop_running = 0x0;

}

/**

 * 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 - AN15.

 *

 * @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 = ADMUX_OPT + which;

        } else {

                ADMUX = ADMUX_OPT + 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; //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 - AN15.

 *

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

 * 

 * @see analog_init, analog8

 **/

unsigned int analog10(int which)

{

        int adc_h;

        int adc_l;

        // Let any previous conversion finish

        while (ADCSRA & _BV(ADSC));

        if(which < EXT_MUX) {

                ADMUX = ADMUX_OPT + which;

        } else {

                ADMUX = ADMUX_OPT + EXT_MUX;

                set_adc_mux(which - 8);

        }

        // Start the conversion

        ADCSRA |= _BV(ADSC);

        // Wait for the conversion to finish

        while (ADCSRA & _BV(ADSC));

        adc_l = ADCL;

        adc_h = ADCH;

        return ((adc_h << 2) | (adc_l >> 6));

}

/**

 * 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 analog8(WHEEL_PORT);

}

/**

 * Sets the value of the external analog mux. Values are read

 *         on AN7 physical port. (AN8 - AN15 are "virtual" ports).

 *

 * @param which which analog mux port (0-7) which corresponds

 *                   to AN8-AN15.

 *

 * @bug FIX THIS IN THE NEXT BOARD REVISION:

 *                ADDR2 ADDR1 ADDR0

 *                G2.G4.G3 set mux to port 0-7 via vinary selection

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

 *

 * @see analog_init

 **/

void set_adc_mux(int which)

{  

  // mask so only proper bits are possible.  

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

}

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

ISR(ADC_vect) {

        static volatile int adc_prev_loop_running = 0;

    // Need these local variables to read ADCH and ADCL in the correct order

        int adc_h = 0;

        int adc_l = 0;

        //Store the value only if this read isn't for the BOM

        if (ADMUX != BOM_PORT) {

            // Read ADCL before ADCH otherwise the registers change in the middle

                adc_l = ADCL;

                adc_h = ADCH;

                an_val[adc_current_port - 1].adc10 = (adc_h << 2) | (adc_l >> 6);

                an_val[adc_current_port - 1].adc8 = adc_h;

        }

        //Save the result only if we just turned off the loop

        if (!adc_loop_running && !adc_prev_loop_running)

                return;

        adc_prev_loop_running = adc_loop_running;

        //Skip AN7 because it is not a real port

        if (adc_current_port == AN6) {

                ADMUX = ADMUX_OPT | EXT_MUX;

                set_adc_mux(AN8 - 8);

                adc_current_port = AN8;

        //Wrap around

        } else if (adc_current_port == AN11) {

                adc_current_port = AN1;

                ADMUX = ADMUX_OPT | adc_current_port;

        //Normal increment

        } else {

                adc_current_port++;

                if(adc_current_port < EXT_MUX) {

                        ADMUX = ADMUX_OPT | adc_current_port;

                } else {

                        ADMUX = ADMUX_OPT | EXT_MUX;

                        set_adc_mux(adc_current_port - 8);

                }

        }

        //Initiate next conversion only if we are running a loop

        if (!adc_loop_running)

                return;

        ADCSRA |= _BV(ADSC);

        return;

}