//**************************************************************************************
//
//! adc_init
//!
//! @param ADCx: ADCx.ADC_CHANNEL, ADCx.ADC_PRESCALAR, ADCx.ADC_REF,
//! ADCx.ADC_MODE
//!
//! @return none
//!
//! @brief This function is used to initialize the ADC peripherial.
//
//**************************************************************************************
void adc_init(ADC_Init ADCx)
{
adc_set_channel(ADCx.ADC_CHANNEL);
adc_pin_init(ADCx.ADC_CHANNEL);
adc_set_prescalar(ADCx.ADC_PRESCALAR);
adc_set_ref(ADCx.ADC_REF);
adc_set_mode(ADCx.ADC_MODE);
}
int
main (void)
{
// This isn't what we're testing exactly, but we need to know if its
// working or not to interpret other results.
term_io_init ();
PFP ("\n");
PFP ("\n");
PFP ("term_io_init() worked.\n");
PFP ("\n");
// FIXME: audit item: I like to put const after type as Dan Saks advises
uint8_t const aip = 0; // Analog Input Pin (from 0 for ADC0 to 5 for ADC5)
adc_init (ADC_REFERENCE_AVCC);
PFP ("Finished adc_init().\n");
adc_pin_init (aip);
// This register bit test is hardwired to match the chosen aip value.
// The initialization should have done this, but we can't tell just by
// observing that the ADC reads voltages correctly, so we check here.
if ( ! (DIDR0 & _BV (ADC0D)) ) {
PFP (
"failure: Digital input disable bit ADC0D of register DIDR0 not "
"set\n" );
assert (0);
}
PFP ("Finished adc_pin_init().\n");
PFP ("\n");
// Configure pin A1 (aka PC1) as an output, starting out low.
PORTC &= ~(_BV (PORTC1));
//FIXXME: could be a no-op, which recent avr libc have a macro for
loop_until_bit_is_clear (PORTC, PORTC1);
DDRC |= _BV (DDC1);
while ( 1 )
{
float const supply_voltage = 5.0;
uint16_t raw = adc_read_raw (aip);
float tap_voltage = adc_read_voltage (aip, supply_voltage);
PFP ("ADC input voltage: %f (%d raw)\r\n", tap_voltage, raw);
toggle_pc1 ();
float const mspr = 500.0; // Milliseconds Per Reading (and LED toggle)
_delay_ms (mspr);
}
return 0;
}
//**************************************************************************************
//
//! adc_set_channel
//!
//! @param adcChannel: ADC0, ADC1, ADC2, ADC3, ADC4, ADC5
//!
//! @return none
//!
//! @brief This function is used to set the ADC channel for ADC peripherial.
//
//**************************************************************************************
void adc_set_channel(ADC_Channel adcChannel)
{
ADMUX &= 0xF0;
ADMUX |= (adcChannel << MUX0);
adc_pin_init(adcChannel);
}
