/**
* \internal
* \brief Test differential conversion with gain in 12-bit mode using the DAC
*
* This test outputs a gain compensated level on DAC output that should result
* in a value of half maximum positive value on the ADC.
*
* These values are then measured using the ADC on the pins that are connected
* to the DAC channel, and the results are compared and checked to see if they
* are within the acceptable range of values that passes the test.
*
* \param test Current test case.
*/
static void run_differential_12bit_with_gain_conversion_test(
const struct test_case *test)
{
// Number of MUX inputs that are to be read
const uint8_t num_inputs = 2;
/* Connection between DAC outputs and ADC MUX inputs.
* Only the high nibble on PORTA is possible for gain.
* input 4, 6 is connected to DACA0
* input 5, 7 is connected to DACA1.
*/
const uint8_t channel_pos[] = {4, 6};
const uint8_t channel_neg[] = {5, 7};
/*
* Go through gain level up to 8, since any higher gives too much
* propagated error for sensible unit test limits.
*/
const uint8_t gain[] = {1, 2, 4, 8};
uint8_t gain_index;
uint8_t adc_channel;
uint8_t mux_index;
int16_t results[2];
struct dac_config dac_conf;
struct adc_config adc_conf;
// Configure ADC
adc_read_configuration(&ADCA, &adc_conf);
adc_set_conversion_parameters(&adc_conf, ADC_SIGN_ON, ADC_RES_12,
ADC_REF_BANDGAP);
adc_set_clock_rate(&adc_conf, 2000UL);
adc_set_conversion_trigger(&adc_conf, ADC_TRIG_MANUAL, 1, 0);
adc_write_configuration(&ADCA, &adc_conf);
// Configure DAC
dac_read_configuration(&DACA, &dac_conf);
dac_set_conversion_parameters(&dac_conf, DAC_REF_BANDGAP,
DAC_ADJ_RIGHT);
dac_set_active_channel(&dac_conf, DAC_CH0 | DAC_CH1, 0);
dac_set_conversion_trigger(&dac_conf, 0, 0);
dac_set_conversion_interval(&dac_conf, 10);
dac_set_refresh_interval(&dac_conf, 20);
dac_write_configuration(&DACA, &dac_conf);
dac_enable(&DACA);
// Set negative output to zero
dac_wait_for_channel_ready(&DACA, DAC_CH1);
dac_set_channel_value(&DACA, DAC_CH1, DAC_MIN);
for (gain_index = 0; gain_index < sizeof(gain); gain_index++) {
// Set positive output to half positive range adjusted to gain
dac_wait_for_channel_ready(&DACA, DAC_CH0);
dac_set_channel_value(&DACA, DAC_CH0, DAC_MAX /
(gain[gain_index] * 2));
/* Read all ADC pins connected to active DAC output.
* All channels are converted NUM_SAMPLES times and the
* final value used for the assert is an average.
*/
for (adc_channel = 0; adc_channel < NUM_CHANNELS;
adc_channel++) {
differential_signed_average(&ADCA, 1 << adc_channel,
channel_pos, channel_neg, num_inputs,
results, gain[gain_index]);
for (mux_index = 0; mux_index < num_inputs;
mux_index++) {
verify_signed_result(test,
ADC_SIGNED_12BIT_MAX / 2,
results[mux_index],
adc_channel,
channel_pos[mux_index],
channel_neg[mux_index],
ADC_SIGNED_12BIT_MIN,
ADC_SIGNED_12BIT_MAX,
gain[gain_index], true);
}
}
}
}
/**
* \internal
* \brief Test single ended conversion in 8-bit mode using the DAC
*
* This tests output three different values on the two DAC channels:
* - 0 (output analog value is greater than 0, as the DAC cannot go that low)
* - 1/2 * \ref DAC_MAX Half of the maximum value of the DAC
* - \ref DAC_MAX The maximum value (VREF) of the DAC.
*
* These values are then measured using the ADC on the pins that are connected
* to the DAC channel, using all available ADC channels and the results are
* compared and checked to see if they are within the acceptable range of
* values that passes the test.
*
* \param test Current test case.
*/
static void run_single_ended_8bit_conversion_test(
const struct test_case *test)
{
// Number of MUX inputs that are to be read
const uint8_t num_inputs = 4;
/* Connection between DAC outputs and ADC MUX inputs
* input 0, 2, 4, 6 is connected to DACA0
* input 1, 3, 5, 7 is connected to DACA1.
*/
const uint8_t channelgroup[2][4] = {{0, 2, 4, 6}, {1, 3, 5, 7}};
uint8_t dac_channel;
uint8_t adc_channel;
uint8_t mux_index;
uint16_t results[4];
struct dac_config dac_conf;
struct adc_config adc_conf;
// Configure ADC
adc_read_configuration(&ADCA, &adc_conf);
adc_set_conversion_parameters(&adc_conf, ADC_SIGN_OFF, ADC_RES_8,
ADC_REF_BANDGAP);
adc_set_clock_rate(&adc_conf, 2000UL);
adc_set_conversion_trigger(&adc_conf, ADC_TRIG_MANUAL, 1, 0);
adc_write_configuration(&ADCA, &adc_conf);
// Configure DAC
dac_read_configuration(&DACA, &dac_conf);
dac_set_conversion_parameters(&dac_conf, DAC_REF_BANDGAP, DAC_ADJ_RIGHT);
dac_set_active_channel(&dac_conf, DAC_CH0 | DAC_CH1, 0);
dac_set_conversion_trigger(&dac_conf, 0, 0);
dac_set_conversion_interval(&dac_conf, 10);
dac_set_refresh_interval(&dac_conf, 20);
dac_write_configuration(&DACA, &dac_conf);
dac_enable(&DACA);
// Set outputs as zero
dac_wait_for_channel_ready(&DACA, DAC_CH0 | DAC_CH1);
dac_set_channel_value(&DACA, DAC_CH0, DAC_MIN);
dac_set_channel_value(&DACA, DAC_CH1, DAC_MIN);
for(dac_channel = 0; dac_channel < 2; dac_channel++) {
/* Read all ADC pins connected to active DAC output.
* All channels are converted NUM_SAMPLES times and the
* final value used for the assert is an average.
*/
for (adc_channel = 0; adc_channel < NUM_CHANNELS;
adc_channel++) {
single_ended_unsigned_average(&ADCA, 1 << adc_channel,
(uint8_t *)&channelgroup[dac_channel],
num_inputs, results);
for (mux_index = 0; mux_index < num_inputs;
mux_index++) {
verify_unsigned_result(test,
ADC_ZERO,
results[mux_index],
dac_channel,
adc_channel,
channelgroup[dac_channel]
[mux_index],
ADC_UNSIGNED_8BIT_MAX, false);
}
}
}
// Set outputs as 1/2 * MAX_VALUE
dac_wait_for_channel_ready(&DACA, DAC_CH0 | DAC_CH1);
dac_set_channel_value(&DACA, DAC_CH0, DAC_MAX / 2);
dac_set_channel_value(&DACA, DAC_CH1, DAC_MAX / 2);
for(dac_channel = 0; dac_channel < 2; dac_channel++) {
/* Read all ADC pins connected to active DAC output.
* All channels are converted NUM_SAMPLES times and the
* final value used for the assert is an average.
*/
for (adc_channel = 0; adc_channel < NUM_CHANNELS;
adc_channel++) {
single_ended_unsigned_average(&ADCA, 1 << adc_channel,
(uint8_t *)&channelgroup[dac_channel],
num_inputs, results);
for (mux_index = 0; mux_index < num_inputs;
mux_index++) {
verify_unsigned_result(test,
ADC_UNSIGNED_8BIT_MAX / 2,
results[mux_index],
dac_channel,
adc_channel,
channelgroup[dac_channel]
[mux_index],
ADC_UNSIGNED_8BIT_MAX, false);
}
}
}
// Set outputs as MAX_VALUE
dac_wait_for_channel_ready(&DACA, DAC_CH0 | DAC_CH1);
dac_set_channel_value(&DACA, DAC_CH0, DAC_MAX);
dac_set_channel_value(&DACA, DAC_CH1, DAC_MAX);
for(dac_channel = 0; dac_channel < 2; dac_channel++) {
/* Read all ADC pins connected to active DAC output.
* All channels are converted NUM_SAMPLES times and the
* final value used for the assert is an average.
*/
for (adc_channel = 0; adc_channel < NUM_CHANNELS;
adc_channel++) {
single_ended_unsigned_average(&ADCA, 1 << adc_channel,
(uint8_t *)&channelgroup[dac_channel],
num_inputs, results);
for (mux_index = 0; mux_index < num_inputs;
mux_index++) {
verify_unsigned_result(test,
ADC_UNSIGNED_8BIT_MAX,
results[mux_index],
dac_channel,
adc_channel,
channelgroup[dac_channel]
[mux_index],
ADC_UNSIGNED_8BIT_MAX, false);
}
}
}
}
/**
* \internal
* \brief Test differential conversion in 12-bit mode using the DAC
*
* This tests output three different values on the two DAC channels:
* - 1/2 * \ref DAC_MAX on both outputs to get a differential zero
* - \ref DAC_MAX on positive and \ref DAC_MIN on negative to get max positive
* result
* - \ref DAC_MIN on positive and \ref DAC_MAX on negative to get max negative
* result
*
* These values are then measured using the ADC on the pins that are connected
* to the DAC channel, and the results are compared and checked to see if they
* are within the acceptable range of values that passes the test.
*
* \param test Current test case.
*/
static void run_differential_12bit_conversion_test(
const struct test_case *test)
{
// Number of MUX inputs that are to be read
const uint8_t num_inputs = 4;
/* Connection between DAC outputs and ADC MUX inputs
* input 0, 2, 4, 6 is connected to DACA0
* input 1, 3, 5, 7 is connected to DACA1.
*/
const uint8_t channel_pos[] = {0, 2, 4, 6};
const uint8_t channel_neg[] = {1, 3, 5, 7};
uint8_t adc_channel;
uint8_t mux_index;
int16_t results[4];
struct dac_config dac_conf;
struct adc_config adc_conf;
// Configure ADC
adc_read_configuration(&ADCA, &adc_conf);
adc_set_conversion_parameters(&adc_conf, ADC_SIGN_ON, ADC_RES_12,
ADC_REF_BANDGAP);
adc_set_clock_rate(&adc_conf, 2000UL);
adc_set_conversion_trigger(&adc_conf, ADC_TRIG_MANUAL, 1, 0);
adc_write_configuration(&ADCA, &adc_conf);
// Configure DAC
dac_read_configuration(&DACA, &dac_conf);
dac_set_conversion_parameters(&dac_conf, DAC_REF_BANDGAP,
DAC_ADJ_RIGHT);
dac_set_active_channel(&dac_conf, DAC_CH0 | DAC_CH1, 0);
dac_set_conversion_trigger(&dac_conf, 0, 0);
dac_set_conversion_interval(&dac_conf, 10);
dac_set_refresh_interval(&dac_conf, 20);
dac_write_configuration(&DACA, &dac_conf);
dac_enable(&DACA);
// Set outputs to same (1/2 * MAX_VALUE) to get zero
dac_wait_for_channel_ready(&DACA, DAC_CH0 | DAC_CH1);
dac_set_channel_value(&DACA, DAC_CH0, DAC_MAX / 2);
dac_set_channel_value(&DACA, DAC_CH1, DAC_MAX / 2);
/* Read all ADC pins connected to active DAC output.
* All channels are converted NUM_SAMPLES times and the
* final value used for the assert is an average.
*/
for (adc_channel = 0; adc_channel < NUM_CHANNELS; adc_channel++) {
differential_signed_average(&ADCA, 1 << adc_channel,
channel_pos, channel_neg, num_inputs, results,
1);
for (mux_index = 0; mux_index < num_inputs; mux_index++) {
verify_signed_result(test, ADC_ZERO,
results[mux_index], adc_channel,
channel_pos[mux_index],
channel_neg[mux_index],
ADC_SIGNED_12BIT_MIN,
ADC_SIGNED_12BIT_MAX, 1, true);
}
}
// Set output to max positive range for positive result
dac_wait_for_channel_ready(&DACA, DAC_CH0 | DAC_CH1);
dac_set_channel_value(&DACA, DAC_CH0, DAC_MAX);
dac_set_channel_value(&DACA, DAC_CH1, DAC_MIN);
/* Read all ADC pins connected to active DAC output.
* All channels are converted NUM_SAMPLES times and the
* final value used for the assert is an average.
*/
for (adc_channel = 0; adc_channel < NUM_CHANNELS; adc_channel++) {
differential_signed_average(&ADCA, 1 << adc_channel,
channel_pos, channel_neg, num_inputs, results,
1);
for (mux_index = 0; mux_index < num_inputs; mux_index++) {
verify_signed_result(test, ADC_SIGNED_12BIT_MAX,
results[mux_index], adc_channel,
channel_pos[mux_index],
channel_neg[mux_index],
ADC_SIGNED_12BIT_MIN,
ADC_SIGNED_12BIT_MAX, 1, true);
}
}
// Set output to max negative range for negative result
dac_wait_for_channel_ready(&DACA, DAC_CH0 | DAC_CH1);
dac_set_channel_value(&DACA, DAC_CH0, DAC_MIN);
dac_set_channel_value(&DACA, DAC_CH1, DAC_MAX);
/* Read all ADC pins connected to active DAC output.
* All channels are converted NUM_SAMPLES times and the
* final value used for the assert is an average.
*/
for (adc_channel = 0; adc_channel < NUM_CHANNELS; adc_channel++) {
differential_signed_average(&ADCA, 1 << adc_channel,
channel_pos, channel_neg, num_inputs, results,
1);
for (mux_index = 0; mux_index < num_inputs; mux_index++) {
verify_signed_result(test, ADC_SIGNED_12BIT_MIN,
results[mux_index], adc_channel,
channel_pos[mux_index],
channel_neg[mux_index],
ADC_SIGNED_12BIT_MIN,
ADC_SIGNED_12BIT_MAX, 1, true);
}
}
}
int main(void)
{
struct dac_config conf;
board_init();
sysclk_init();
// Initialize the dac configuration.
dac_read_configuration(&OUTPUT_DAC, &conf);
/* Create configuration:
* - AVCC as reference, right adjusted channel value
* - both DAC channels active, no internal output
* - manually triggered conversions on both channels
* - 2 us conversion intervals
* - 10 us refresh intervals
*/
dac_set_conversion_parameters(&conf, DAC_REF_AVCC, DAC_ADJ_RIGHT);
dac_set_active_channel(&conf, DAC_CH0 | DAC_CH1, 0);
dac_set_conversion_trigger(&conf, 0, 0);
#if XMEGA_DAC_VERSION_1
dac_set_conversion_interval(&conf, 10);
dac_set_refresh_interval(&conf, 20);
#endif
dac_write_configuration(&OUTPUT_DAC, &conf);
dac_enable(&OUTPUT_DAC);
dac_wait_for_channel_ready(&OUTPUT_DAC, DAC_CH0 | DAC_CH1);
dac_set_channel_value(&OUTPUT_DAC, DAC_CH0, 0);
dac_set_channel_value(&OUTPUT_DAC, DAC_CH1, 0);
dac_wait_for_channel_ready(&OUTPUT_DAC, DAC_CH0 | DAC_CH1);
#if !XMEGA_E
// Configure timer/counter to generate events at conversion rate.
sysclk_enable_module(SYSCLK_PORT_C, SYSCLK_TC0);
TCC0.PER = (sysclk_get_per_hz() / RATE_OF_CONVERSION) - 1;
// Configure event channel 0 to generate events upon T/C overflow.
sysclk_enable_module(SYSCLK_PORT_GEN, SYSCLK_EVSYS);
EVSYS.CH0MUX = EVSYS_CHMUX_TCC0_OVF_gc;
// Start the timer/counter.
TCC0.CTRLA = TC_CLKSEL_DIV1_gc;
#else
// Configure timer/counter to generate events at conversion rate.
sysclk_enable_module(SYSCLK_PORT_C, SYSCLK_TC4);
TCC4.PER = (sysclk_get_per_hz() / RATE_OF_CONVERSION) - 1;
// Configure event channel 0 to generate events upon T/C overflow.
sysclk_enable_module(SYSCLK_PORT_GEN, SYSCLK_EVSYS);
EVSYS.CH0MUX = EVSYS_CHMUX_TCC4_OVF_gc;
// Start the timer/counter.
TCC4.CTRLA = TC45_CLKSEL_DIV1_gc;
#endif
/* Write samples to the DAC channel every time it is ready.
* Conversions are triggered by the timer/counter.
*/
do {
/* Wait for channels to get ready for new values, then set the
* value of one to 10% and the other to 90% of maximum.
*/
wait_for_timer();
dac_set_channel_value(&OUTPUT_DAC, DAC_CH0, 410);
dac_set_channel_value(&OUTPUT_DAC, DAC_CH1, 3686);
wait_for_timer();
dac_set_channel_value(&OUTPUT_DAC, DAC_CH0, 3686);
dac_set_channel_value(&OUTPUT_DAC, DAC_CH1, 410);
} while (1);
}
