Revision 1736
joystick demo - not working yet
analog.c | ||
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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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volatile int adc_loop_status = ADC_LOOP_STOPPED; |
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volatile int adc_sig_stop_loop = 0; |
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volatile int adc_current_port = 0; |
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volatile 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 EDIT: changed to 8MHz |
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ADCSRA = 0; |
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ADCSRA |= _BV(ADEN) | _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 loop if requested |
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//if (start_conversion) |
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//analog_start_loop(); |
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//Conversion loop disabled by default |
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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_status |
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**/ |
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void analog_start_loop(void) { |
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if(adc_loop_status != ADC_LOOP_RUNNING){ |
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//Start the conversion, enable ADC interrupt |
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ADCSRA |= _BV(ADIE); |
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ADCSRA |= _BV(ADSC); |
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adc_loop_status = ADC_LOOP_RUNNING; |
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} |
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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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* @see analog_start_loop, analog_loop_status |
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**/ |
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void analog_stop_loop() { |
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//Signal to stop after the next conversion |
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adc_sig_stop_loop = 1; |
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} |
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/** |
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* Returns the status of loop. 0 for stopped. |
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* 1 for running. 2 for paused. |
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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_status(void) { |
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return adc_loop_status; |
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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 analog_get8(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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/*int adc_h = 0; |
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int adc_l = 0; |
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if(adc_loop_status != ADC_LOOP_RUNNING) return; |
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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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//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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//Stop loop if signal is set |
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if(adc_sig_stop_loop) { |
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adc_sig_stop_loop = 0; |
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adc_loop_status = ADC_LOOP_STOPPED; |
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return; |
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} |
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//Start next conversion |
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ADCSRA |= _BV(ADSC);*/ |
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} |
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