int analogRead(uint8_t pin)
{
uint8_t low, high, ch = analogInPinToBit(pin);
// 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).
ADMUX = (analog_reference << 6) | (pin & 0x0f);
// without a delay, we seem to read from the wrong channel
//delay(1);
// start the conversion
sbi(ADCSRA, ADSC);
// 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.
low = ADCL;
high = ADCH;
// combine the two bytes
return (high << 8) | low;
}
int analogRead(uint8_t pin)
{
uint8_t low, high, ch = analogInPinToBit(pin);
sbi(ADCSRA,ADEN);
// the low 4 bits of ADMUX select the ADC channel
ADMUX = (ADMUX & (unsigned int) 0xf0) | (ch & (unsigned int) 0x0f);
// without a delay, we seem to read from the wrong channel
//delay(1);
// start the conversion
sbi(ADCSRA, ADSC);
// 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.
low = ADCL;
high = ADCH;
// combine the two bytes
return (high << 8) | low;
}
//*********************************************************************
int analogRead(uint8_t pin)
{
int analogValue;
unsigned int offset; // buffer offset to point to the base of the idle buffer
unsigned int param4;
uint8_t channelNumber;
//* in most cases (except the uno board) this will be a 1 to 1 mapping
channelNumber = analogInPinToBit(pin);
//* May 1, 2011 Gene Apperson of Digitlent sent me PIC32MX5XX-6XX-7XX Errata.pdf
//* item #26 documents a condition that I/O pins take time if previously set to outputs
//* first attempt, set all to 0
// AD1PCFG = 0;
// configure and enable the ADC
CloseADC10(); // ensure the ADC is off before setting the configuration
// define setup parameters for OpenADC10
// Turn module on | ouput in integer | trigger mode auto | enable autosample
#define PARAM1 ADC_FORMAT_INTG16 | ADC_CLK_AUTO | ADC_AUTO_SAMPLING_ON
// define setup parameters for OpenADC10
// ADC ref external | disable offset test | disable scan mode | perform 2 samples | use dual buffers | use alternate mode
#define PARAM2 ADC_VREF_AVDD_AVSS | ADC_OFFSET_CAL_DISABLE | ADC_SCAN_OFF | ADC_SAMPLES_PER_INT_1 | ADC_ALT_BUF_ON
// define setup parameters for OpenADC10
// use ADC internal clock | set sample time
#define PARAM3 ADC_CONV_CLK_INTERNAL_RC | ADC_SAMPLE_TIME_15
// define setup parameters for OpenADC10
// set AN4 and AN5 as analog inputs
param4 = channelNumber;
// define setup parameters for OpenADC10
// do not assign channels to scan
#define PARAM5 SKIP_SCAN_ALL
// use ground as neg ref for A | use AN4 for input A | use ground as neg ref for A | use AN5 for input B
// SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN4 | ADC_CH0_NEG_SAMPLEB_NVREF | ADC_CH0_POS_SAMPLEB_AN5); // configure to sample AN4 & AN5
// SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN0 | ADC_CH0_NEG_SAMPLEB_NVREF | ADC_CH0_POS_SAMPLEB_AN1); // configure to sample AN4 & AN5
// OpenADC10( PARAM1, PARAM2, PARAM3, PARAM4, PARAM5 ); // configure ADC using the parameters defined above
switch(channelNumber)
{
case 0:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN0);
break;
case 1:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN1);
break;
case 2:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN2);
break;
case 3:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN3);
break;
case 4:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN4);
break;
case 5:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN5);
break;
case 6:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN6);
break;
case 7:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN7);
break;
case 8:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN8);
break;
case 9:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN9);
break;
case 10:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN10);
break;
case 11:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN11);
break;
case 12:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN12);
break;
case 13:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN13);
break;
case 14:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN14);
break;
case 15:
SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN15);
break;
}
// configure to sample what ever pin was specified
OpenADC10( PARAM1, PARAM2, PARAM3, param4, PARAM5 ); // configure ADC using the parameters defined above
EnableADC10(); // Enable the ADC
//* A delay is needed for the the ADC start up time
//* this value started out at 1 millisecond, I dont know how long it needs to be
//* 99 uSecs will give us the same approximate sampling rate as the AVR chip
// delay(1);
delayMicroseconds(99);
while ( ! mAD1GetIntFlag() )
{
// wait for the first conversion to complete so there will be vaild data in ADC result registers
}
analogValue = ReadADC10(0);
mAD1ClearIntFlag();
return (analogValue);
}
