ArduinoTaikoController/AnalogReadNow.cpp

70 lines
2.1 KiB
C++

#include "AnalogReadNow.h"
#include "wiring_private.h"
#include "pins_arduino.h"
void analogSwitchPin(uint8_t pin)
{
#if defined(analogPinToChannel)
#if defined(__AVR_ATmega32U4__)
if (pin >= 18) pin -= 18; // allow for channel or pin numbers
#endif
pin = analogPinToChannel(pin);
#elif defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
if (pin >= 54) pin -= 54; // allow for channel or pin numbers
#elif defined(__AVR_ATmega32U4__)
if (pin >= 18) pin -= 18; // allow for channel or pin numbers
#elif defined(__AVR_ATmega1284__) || defined(__AVR_ATmega1284P__) || defined(__AVR_ATmega644__) || defined(__AVR_ATmega644A__) || defined(__AVR_ATmega644P__) || defined(__AVR_ATmega644PA__)
if (pin >= 24) pin -= 24; // allow for channel or pin numbers
#else
if (pin >= 14) pin -= 14; // allow for channel or pin numbers
#endif
#if defined(ADCSRB) && defined(MUX5)
// the MUX5 bit of ADCSRB selects whether we're reading from channels
// 0 to 7 (MUX5 low) or 8 to 15 (MUX5 high).
ADCSRB = (ADCSRB & ~(1 << MUX5)) | (((pin >> 3) & 0x01) << MUX5);
#endif
// set the analog reference (high two bits of ADMUX) and select the
// channel (low 4 bits). this also sets ADLAR (left-adjust result)
// to 0 (the default).
#if defined(ADMUX)
#if defined(__AVR_ATtiny25__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
ADMUX = (DEFAULT << 4) | (pin & 0x07);
#else
ADMUX = (DEFAULT << 6) | (pin & 0x07);
#endif
#endif
// without a delay, we seem to read from the wrong channel
//delay(1);
#if defined(ADCSRA) && defined(ADCL)
// start the conversion
sbi(ADCSRA, ADSC);
#endif
}
int analogReadNow()
{
#if defined(ADCSRA) && defined(ADCL)
// ADSC is cleared when the conversion finishes
while (bit_is_set(ADCSRA, ADSC));
// we have to read ADCL first; doing so locks both ADCL
// and ADCH until ADCH is read. reading ADCL second would
// cause the results of each conversion to be discarded,
// as ADCL and ADCH would be locked when it completed.
uint8_t low, high;
low = ADCL;
high = ADCH;
// combine the two bytes
return (high << 8) | low;
#else
// we dont have an ADC, return 0
return 0;
#endif
}