58 lines
1.5 KiB
C
58 lines
1.5 KiB
C
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/**
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* Analog to Digital converter routines
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*
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* @copyright 2012 Institute Automation of Complex Power Systems (ACS), RWTH Aachen University
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* @license http://www.gnu.org/licenses/gpl.txt GNU Public License
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* @author Steffen Vogel <info@steffenvogel.de>
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*/
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#include <avr/io.h>
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#include "adc.h"
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/**
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* Initialisierung Analog to digital Converter (ADC)
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*/
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void adc_init() {
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uint16_t result;
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ADC_DDR = 0x00; // Pins als Eing<6E>nge
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ADC_PORT = 0x00; // Pullups deaktivieren
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ADMUX = (1<<REFS1) | (1<<REFS0); // interne 2.56V als Referenz benutzen
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ADCSRA = (1<<ADPS2) | (1<<ADPS1) | (1<<ADPS0); // Frequenzvorteiler
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ADCSRA |= (1<<ADEN); // ADC aktivieren
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ADCSRA |= (1<<ADIE); // ADC Interrupts erlauben
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ADCSRA |= (1<<ADSC); // starte eine ADC-Wandlung
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while (ADCSRA & (1<<ADSC) ) { } // auf Abschluss der Konvertierung warten
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result = ADC;
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}
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/**
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* Auslesen des Kanals
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*/
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uint16_t adc_read(uint8_t channel) {
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// Kanal waehlen, ohne andere Bits zu beeinflu<6C>en
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ADMUX = (ADMUX & ~(0x1F)) | (channel & 0x1F);
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ADCSRA |= (1<<ADSC); // eine Wandlung "single conversion"
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while (ADCSRA & (1<<ADSC) ) { } // auf Abschluss der Konvertierung warten
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return ADC; // ADC auslesen und zur<75>ckgeben
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}
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/**
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* Auslesen des Kanals mit Mittelwertr<EFBFBD>ckgabe
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*/
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uint16_t adc_read_avg( uint8_t channel, uint8_t average) {
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uint32_t result = 0;
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for (uint8_t i = 0; i < average; ++i ) {
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result += adc_read(channel);
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}
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return (uint16_t) (result / average);
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}
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