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/**
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 * Copyright (c) 2007 Colony Project
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 * 
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 * Permission is hereby granted, free of charge, to any person
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 * obtaining a copy of this software and associated documentation
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 * files (the "Software"), to deal in the Software without
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 * restriction, including without limitation the rights to use,
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 * copy, modify, merge, publish, distribute, sublicense, and/or sell
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 * copies of the Software, and to permit persons to whom the
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 * Software is furnished to do so, subject to the following
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 * conditions:
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 * 
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 * The above copyright notice and this permission notice shall be
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 * included in all copies or substantial portions of the Software.
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 * 
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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 * OTHER DEALINGS IN THE SOFTWARE.
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 **/
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/**
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 * @file analog.c
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 * @brief Analog input and output
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 *
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 * Contains functions for manipulating the ADC on the Dragonfly board.
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 * 
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 * @author Colony Project, CMU Robotics Club
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 * originally taken from fwr analog file (author: Tom Lauwers)
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 * loop code written by Kevin Woo and James Kong
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 **/
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#include <util/delay.h>
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#include <avr/interrupt.h>
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#include "analog.h"
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#include "serial.h"
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// Internal Function Prototypes
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void set_adc_mux(int which);
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/**
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 * @defgroup analog Analog
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 * Functions for manipulation the ADC on the dragonfly board.
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 * All definitions may be found in analog.h.
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 *
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 * @{
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 **/
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int adc_loop_running = 0;
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int adc_current_port = 0;
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adc_t an_val[11];
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/**
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 * Initializes the ADC.
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 * Call analog_init before reading from the analog ports.
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 *
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 * @see analog8, analog10, analog_get8, analog_get10
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 *
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 * @bug First conversion takes a performance penalty of
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 * 25 vs. 13 ADC clock cycles of successive conversions.
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 * Analog_init should run a dummy conversion to pre-empt
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 * this.
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 *
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 * For good 10-bit precision, ACD clock must be between
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 * 50kHz and 200kHz. Currently, ADC clock is fixed at
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 * 125kHz using 1/64prescalar. However, most code uses
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 * 8-bit precision which can work at ADC clock speeds
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 * higher than 200kHz. Experimental tests needed to
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 * determine highest clock speed for accurate 8-bit ADC.
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 *
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 **/
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void analog_init(int start_conversion) {
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        for (int i = 0; i < 11; i++) {
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                an_val[i].adc10 = 0;
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                an_val[i].adc8 = 0;
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        }
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        // ADMUX register
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        // Bit 7,6 - Set voltage reference to AVcc (0b01)
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        // Bit 5 - ADLAR set to simplify moving from register
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        // Bit 4 - X
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        // Bit 3:0 - Sets the current channel
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        // Initializes to read from AN1 first (AN0 is reservered for the BOM)
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        ADMUX = 0;
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        ADMUX |= ADMUX_OPT | _BV(MUX0);
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        // ADC Status Register A
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        // Bit 7 - ADEN is set (enables analog)
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        // Bit 6 - Start conversion bit is set (must be done once for free-running mode)
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        // Bit 5 - Enable Auto Trigger (for free running mode) NOT DOING THIS RIGHT NOW
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        // Bit 4 - ADC interrupt flag, 0
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        // Bit 3 - Enable ADC Interrupt (required to run free-running mode)
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        // Bits 2-0 - Set to create a clock divisor of 128, to make ADC clock = 8,000,000/64 = 125kHz
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        ADCSRA = 0;
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        ADCSRA |= _BV(ADEN) | _BV(ADPS2) | _BV(ADPS1) | _BV(ADPS0);
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        // Set external mux lines to outputs
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        DDRG |= 0x1C;
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        // Set up first port for conversions
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        set_adc_mux(0x00);
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        adc_current_port = AN1;
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        //Start the conversion if requested
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        if (start_conversion)
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                analog_start_loop();
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        else
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                analog_stop_loop();
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}        
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/**
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 * Returns the 8-bit analog conversion of which from
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 * the lookup table. If the requested port is the BOM_PORT
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 * you will get an automatic 0 since the BOM_PORT is not
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 * read in the loop and not stored. If you need that port
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 * you should use the functions in bom.c. There is an analog_get8
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 * function which for instant lookups but should be avoided unless
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 * you know what you're doing.
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 *
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 * @param which the port that you want to read
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 *
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 * @bug may cause a seg fault if which is a larger value
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 * than exists in an_val table. Not sure if we should fix
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 * this or not since it would add overhead.
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 *
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 * @return 8-bit analog value for the which port requested
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 *
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 * @see analog10, analog_get8, analog_get10
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 **/
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unsigned int analog8(int which) {
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        if (which == BOM_PORT) {
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                return 0;
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        } else {
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                return an_val[which - 1].adc8;
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        }
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}
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/**
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 * Returns the 10-bit analog conversion of which from
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 * the lookup table. If the requested port is the BOM_PORT
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 * you will get an automatic 0 since the BOM_PORT is not
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 * read in the loop and not stored. If you need that port
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 * you should use the functions in bom.c. There is an analog_get10
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 * function which for instant lookups but should be avoided unless
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 * you know what you are doing.
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 *
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 * @param which the port that you want to read
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 *
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 * @bug may cause a seg fault if which is a larger value
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 * than exists in an_val table. Not sure if we should fix
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 * this or not since it would add overhead.
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 *
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 * @return 10-bit analog value for the which port requested
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 *
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 * @see analog8, analog_get8, analog_get10
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 **/
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unsigned int analog10(int which) {
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        if (which == BOM_PORT) {
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                return 0;
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        } else {
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                return an_val[which - 1].adc10;
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        }
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}
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/**
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 * Starts the analog update loop. Will continue to run
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 * until analog_stop_loop is called.
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 *
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 * @see analog_stop_loop, analog_loop_running
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 **/
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void analog_start_loop(void) {
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        //Start the conversion, enable ADC interrupt
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        ADCSRA |= _BV(ADSC) | _BV(ADIE);
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        adc_loop_running = 0x1;
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}
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/**
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 * Stops the analog update loop. If there is a current
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 * read, it will finish up and be stored before the loop
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 * is interrupted. No further updates will be made until
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 * the loop is started again.
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 *
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 * @param Whether or not to block until current conversion
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 * to complete. Use WAIT_UNTIL_FINISHED or
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 * SKIP_WAIT.
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 *
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 * @see analog_start_loop, analog_loop_running
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 **/
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void analog_stop_loop(int skip_wait) {
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        //Stop the conversion
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        adc_loop_running = 0x0;
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        if(skip_wait) {
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                //Stop the interrupt
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                ADCSRA &= _BV(ADIE);
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                return;
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        }
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        //Wait for the ADC interrupt flag to clear / conversion to complete
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        while(ADCSRA & _BV(ADIF));
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        //Stop the interrupt
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        ADCSRA &= _BV(ADIE);
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}
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/**
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 * Returns the status of loop. 1 for running.
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 * 0 for not running.
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 *
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 * @see analog_start_loop, analog_stop_loop
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 **/
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int analog_loop_running(void) {
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        return adc_loop_running;
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}
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/**
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 * Reads an 8-bit number from an analog port.
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 * analog_init must be called before using this function.
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 * The analog loop must also be stopped before using this
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 * function or you will mess up the lookup table. You
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 * must also reenabled the loop when you are done unless
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 * you are doing more instant reads. See analog_stop_loop
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 * and analog_start_loop for more information about the loop.
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 * 
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 * @param which the analog port to read from. One of
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 * the constants AN0 - AN7.
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 *
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 * @return the 8-bit input to the specified port
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 *
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 * @see analog_init, analog_get10, analog8, analog_stop_loop,
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 * analog_start_loop
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 **/
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unsigned int analog_get8(int which) {        
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        // Let any previous conversion finish
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        while (ADCSRA & _BV(ADSC));
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        if(which < EXT_MUX) {
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                ADMUX = ADMUX_OPT + which;
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        } else {
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                ADMUX = ADMUX_OPT + EXT_MUX;
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                set_adc_mux(which - 8);
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        }
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        // Start the conversion
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        ADCSRA |= _BV(ADSC);
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        // Wait for the conversion to finish
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        while (ADCSRA & _BV(ADSC));
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        return ADCH; //since we left aligned the data, ADCH is the 8 MSB.
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}
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/**
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 * Reads an 10-bit number from an analog port.
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 * analog_init must be called before using this function.
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 * The analog loop must also be stopped before using this
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 * function or you will mess up the lookup table. You
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 * must also reenabled the loop when you are done unless
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 * you are doing more instant reads. See analog_stop_loop
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 * and analog_start_loop for more information about the loop.
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 * 
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 *
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 * @param which the analog port to read from. Typically
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 * a constant, one of AN0 - AN7.
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 *
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 * @return the 10-bit number input to the specified port
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 * 
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 * @see analog_init, analog_get8, analog10, analog_stop_loop,
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 * analog_start_loop
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 **/
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unsigned int analog_get10(int which) {
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        int adc_h;
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        int adc_l;
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        // Let any previous conversion finish
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        while (ADCSRA & _BV(ADSC));
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        if(which < EXT_MUX) {
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                ADMUX = ADMUX_OPT + which;
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        } else {
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                ADMUX = ADMUX_OPT + EXT_MUX;
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                set_adc_mux(which - 8);
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        }
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        // Start the conversion
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        ADCSRA |= _BV(ADSC);
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        // Wait for the conversion to finish
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        while (ADCSRA & _BV(ADSC));
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        adc_l = ADCL;
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        adc_h = ADCH;
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        return ((adc_h << 2) | (adc_l >> 6));
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}
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/**
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 * Returns the current position of the wheel, as an integer
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 * in the range 0 - 255.
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 * analog_init must be called before using this function.
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 *
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 * @return the orientation of the wheel, as an integer in
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 * the range 0 - 255.
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 *
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 * @see analog_init
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 **/
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int wheel(void) {
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        return analog8(WHEEL_PORT);
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}
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/**
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 * Sets the value of the external analog mux. Values are read
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 *         on AN7 physical port. (AN8 - AN15 are "virtual" ports).
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 *
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 * @param which which analog mux port (0-7) which corresponds
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 *                   to AN8-AN15.
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 *
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 * @bug FIX THIS IN THE NEXT BOARD REVISION:
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 *                ADDR2 ADDR1 ADDR0
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 *                G2.G4.G3 set mux to port 0-7 via vinary selection
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 *                math would be much cleaner if it was G4.G3.G2
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 *
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 * @see analog_init
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 **/
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void set_adc_mux(int which) {  
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  // mask so only proper bits are possible.  
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  PORTG = (PORTG & 0xE3) | ((which & 0x03) << 3) | (which & 0x04);
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}
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/**@}**/ //end defgroup
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ISR(ADC_vect) {
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        static volatile int adc_prev_loop_running = 0; 
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        int adc_h = 0;
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        int adc_l = 0;
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        //Store the value only if this read isn't for the BOM
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        if (ADMUX != BOM_PORT) {
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                adc_l = ADCL;
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                adc_h = ADCH;
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                an_val[adc_current_port - 1].adc10 = (adc_h << 2) | (adc_l >> 6);
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                an_val[adc_current_port - 1].adc8 = adc_h;
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        }
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        //Save the result only if we just turned off the loop
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        if (!adc_loop_running && !adc_prev_loop_running)
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                return;
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        adc_prev_loop_running = adc_loop_running;
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        //Skip AN7 because it is not a real port
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        if (adc_current_port == AN6) {
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                ADMUX = ADMUX_OPT | EXT_MUX;
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                set_adc_mux(AN8 - 8);
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                adc_current_port = AN8;
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        //Wrap around
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        } else if (adc_current_port == AN11) {
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                adc_current_port = AN1;
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                ADMUX = ADMUX_OPT | adc_current_port;
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        //Normal increment
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        } else {
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                adc_current_port++;
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                if(adc_current_port < EXT_MUX) {
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                        ADMUX = ADMUX_OPT | adc_current_port;
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                } else {
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                        ADMUX = ADMUX_OPT | EXT_MUX;
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                        set_adc_mux(adc_current_port - 8);
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                }
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        }
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        //Initiate next conversion only if we are running a loop
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        if (!adc_loop_running) {
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                return;
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    } else {
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            ADCSRA |= _BV(ADSC);
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        }
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        return;
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}
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