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allow larger chips to use analog channels 8-15

This commit is contained in:
Michael Moon 2011-06-18 13:28:00 +10:00
parent 43b5c0f0b4
commit 2013effd9c
1 changed files with 35 additions and 8 deletions
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39
analog.c
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@ -12,13 +12,29 @@
#undef DEFINE_TEMP_SENSOR
//! automagically generate analog_mask from DEFINE_TEMP_SENSOR entries in config.h
#define DEFINE_TEMP_SENSOR(name, type, pin, additional) | (((type == TT_THERMISTOR) || (type == TT_AD595)) ? 1 << (pin) : 0)
static const uint8_t analog_mask = 0
#ifdef AIO8_PIN
static const uint16_t analog_mask = 0
#else
static const uint8_t analog_mask = 0
#endif
#include "config.h"
;
#undef DEFINE_TEMP_SENSOR
#ifdef AIO8_PIN
#define AINDEX_MASK 0x1F
#define AINDEX_MAX 15
#define AINDEX_CURRENT ((ADMUX & 0x07) | ((ADCSRB & MASK(MUX5))?0x08:0))
#else
#define AINDEX_MASK 0x0F
#define AINDEX_MAX 7
#define AINDEX_CURRENT (ADMUX & 0x07)
#endif
static uint8_t adc_counter;
static volatile uint16_t adc_result[8] __attribute__ ((__section__ (".bss")));
static volatile uint16_t adc_result[AINDEX_MAX + 1] __attribute__ ((__section__ (".bss")));
//! Configure all registers, start interrupt loop
void analog_init() {
@ -33,11 +49,15 @@ void analog_init() {
// ADC frequency must be less than 200khz or we lose precision. At 16MHz system clock, we must use the full prescale value of 128 to get an ADC clock of 125khz.
ADCSRA = MASK(ADEN) | MASK(ADPS2) | MASK(ADPS1) | MASK(ADPS0);
ADCSRB = 0;
adc_counter = 0;
AIO0_DDR &= ~analog_mask;
DIDR0 = analog_mask & 0x3F;
DIDR0 = analog_mask & 0xFF;
#ifdef DIDR2
DIDR2 = (analog_mask >> 8) & 0xFF;
#endif
// now we start the first conversion and leave the rest to the interrupt
ADCSRA |= MASK(ADIE) | MASK(ADSC);
} /* analog_mask > 0 */
@ -50,15 +70,22 @@ void analog_init() {
ISR(ADC_vect, ISR_NOBLOCK) {
// emulate free-running mode but be more deterministic about exactly which result we have, since this project has long-running interrupts
if (analog_mask > 0) {
adc_result[ADMUX & 0x0F] = ADC;
// store next result
adc_result[AINDEX_CURRENT] = ADC;
// find next channel
do {
adc_counter++;
adc_counter &= 0x07;
adc_counter &= AINDEX_MAX;
} while ((analog_mask & (1 << adc_counter)) == 0);
// start next conversion
ADMUX = (adc_counter) | REFERENCE;
ADMUX = (adc_counter & 0x07) | REFERENCE;
if (adc_counter & 0x08)
ADCSRB |= MASK(MUX5);
else
ADCSRB &= ~MASK(MUX5);
ADCSRA |= MASK(ADSC);
}
}