76 lines
1.5 KiB
C
76 lines
1.5 KiB
C
/* Copyright Robert Olsson */
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#include <avr/pgmspace.h>
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#include <avr/fuse.h>
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#include <avr/eeprom.h>
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#include <stdio.h>
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#include <string.h>
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#include <dev/watchdog.h>
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#include "params.h"
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#include "rss2.h"
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#include "contiki.h"
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#include "adc.h"
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#include "rss2.h"
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uint16_t
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adc_read(uint8_t pin)
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{
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uint16_t volt = 0;
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int i;
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ADMUX = pin; /* ADC pin PA0-PA7 -> 0-7 */
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ADCSRB &= ~(1 << MUX5); /* Needs to write before ADMUX pp 418 */
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ADMUX |= (1 << REFS1) | (1 << REFS0); /* 1.6 */
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/* Maximal Track and Hold time */
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ADCSRA = (1 << ADPS2) | (0 << ADPS1) | (1 << ADPS0); /* Prescaler /32 */
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ADCSRA |= (1 << ADEN); /* Enable the ADC */
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while(!(ADCSRB & (1 << AVDDOK))) ; /* Wait for AVDD ok */
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while(!(ADCSRB & (1 << REFOK))) ; /* Wait for ref ok */
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/* Ignore first result */
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ADCSRA |= (1 << ADSC);
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while(ADCSRA & _BV(ADSC)) {
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}
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ADCW = 0;
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#define RES 4
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for(i = 0; i < RES; i++) {
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/* Start the conversion */
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ADCSRA |= (1 << ADSC);
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/* Wait for conversion */
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while(ADCSRA & (1 << ADSC)) {
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}
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volt += ADCW;
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}
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ADMUX = 0; /* turn off internal vref */
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volt = volt / RES;
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/* Disable the ADC to save power */
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ADCSRA &= ~_BV(ADEN);
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return volt;
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}
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double
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adc_read_v_in(void)
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{
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/* Special treatment for v_in. Schottky voltage drop add */
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return ((double)adc_read(AV_IN)) * V_IN_FACTOR_SCHOTTKY + SCHOTTKY_DROP;
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}
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double
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adc_read_a1(void)
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{
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return ((double)adc_read(A1)) * V_IN_FACTOR;
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}
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double
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adc_read_a2(void)
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{
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return ((double)adc_read(A2)) * V_IN_FACTOR;
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}
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