/**
* \brief Measures and enables offset and gain corrections
*/
static void main_adc_correction(void)
{
/* ADC channel configuration structure */
struct adc_channel_config adcch_conf;
uint16_t offset_correction;
/* Expected value for gain correction at 1.9V
* expected_value = Max. range * 1.9V / (VCC / 1.6)
* Max. range = 12 bits signed = 11 bits unsigned
*/
const uint16_t expected_value
= ((1 << 11) * 1900UL) / (3300L * 1000L / 1600L);
/* Captured value for gain correction */
uint16_t captured_value;
/* DAC Output 0 Volt */
main_dac_output(0);
/* Capture value for 0 Volt */
adc_wait_for_interrupt_flag(&ADCA, ADC_CH0);
adc_wait_for_interrupt_flag(&ADCA, ADC_CH0);
offset_correction = adc_get_unsigned_result(&ADCA, ADC_CH0);
/* Enable offset correction */
adcch_read_configuration(&ADCA, ADC_CH0, &adcch_conf);
adcch_enable_correction(&adcch_conf, offset_correction, 1, 1);
adcch_write_configuration(&ADCA, ADC_CH0, &adcch_conf);
/* DAC Output 1.9 Volts */
main_dac_output(1900);
/* Capture value for 1.9 Volts */
adc_wait_for_interrupt_flag(&ADCA, ADC_CH0);
adc_wait_for_interrupt_flag(&ADCA, ADC_CH0);
captured_value = adc_get_unsigned_result(&ADCA, ADC_CH0);
/* Enable offset & gain correction */
adcch_enable_correction(&adcch_conf, offset_correction, expected_value,
captured_value);
adcch_write_configuration(&ADCA, ADC_CH0, &adcch_conf);
printf("\n\rADC correction: ");
printf("Offset correction %d, ", offset_correction);
if (expected_value > captured_value) {
printf("Gain correction 1.%03u\n\r\n\r", (uint16_t)
((((uint32_t)expected_value - captured_value)
* 1000) / captured_value));
} else {
printf("Gain correction 0.%03u\n\r\n\r", (uint16_t)
(((uint32_t)expected_value
* 1000) / captured_value));
}
}
/**
* \brief Measures and enables offset and gain corrections
*/
static void main_adc_correction_start(void)
{
/* ADC channel configuration structure */
struct adc_channel_config adcch_conf;
static bool correction_measures_done = false;
static uint16_t offset_correction;
/* Expected value for gain correction at 1.9V
* expected_value = Max. range (12 bits unsigned) * 1.9V / (VCC / 1.6)
*/
const uint16_t expected_value
= ((1 << 12) * 1900UL) / (3300L * 1000L / 1600L);
/* Captured value for gain correction */
static uint16_t captured_value;
if (correction_measures_done) {
goto main_adc_correction_enable;
}
printf("\n\r*Measure offset correction\n\r");
printf("Set PA0 pin to GND and press a key to trigge measurement.\n\r");
printf("Warning on STK600: Remove AREF0 jumper to do it.\n\r");
getchar();
/* Capture value for 0 Volt */
adc_start_conversion(&ADCA, ADC_CH0);
adc_wait_for_interrupt_flag(&ADCA, ADC_CH0);
offset_correction = adc_get_unsigned_result(&ADCA, ADC_CH0);
/* Enable offset correction */
adcch_read_configuration(&ADCA, ADC_CH0, &adcch_conf);
adcch_enable_correction(&adcch_conf, offset_correction, 1, 1);
adcch_write_configuration(&ADCA, ADC_CH0, &adcch_conf);
printf("*Measure Gain correction\n\r");
printf("Set PA0 pin to 1.9 Volt");
printf(" and press a key to trigge measurement.\r\n");
printf("Reminder on STK600: Set AREF0 jumper to do it.\n\r");
getchar();
/* Capture value for 1.9 Volts */
adc_start_conversion(&ADCA, ADC_CH0);
adc_wait_for_interrupt_flag(&ADCA, ADC_CH0);
captured_value = adc_get_unsigned_result(&ADCA, ADC_CH0);
correction_measures_done = true;
main_adc_correction_enable:
/* Enable offset & gain correction */
adcch_read_configuration(&ADCA, ADC_CH0, &adcch_conf);
adcch_enable_correction(&adcch_conf, offset_correction, expected_value,
captured_value);
adcch_write_configuration(&ADCA, ADC_CH0, &adcch_conf);
printf("\n\r* ADC correction enabled: ");
printf("Offset correction %d, ", offset_correction);
if (expected_value > captured_value) {
printf("Gain correction 1.%03u\n\r", (uint16_t)
((((uint32_t)expected_value - captured_value)
* 1000) / captured_value));
} else {
printf("Gain correction 0.%03u\n\r", (uint16_t)
(((uint32_t)expected_value
* 1000) / captured_value));
}
}
/**
* \internal
* \brief Test correction conversion in 12-bit mode using the DAC
*
* 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_correction_conversion_test(
const struct test_case *test)
{
int16_t volt_output;
int16_t volt_input;
uint16_t error;
/** Measures and enables offset and gain corrections */
/* ADC channel configuration structure */
struct adc_channel_config adcch_conf;
uint16_t offset_correction;
/* Expected value for gain correction at 1.9V
* expected_value = Max. range * 1.9V / (VCC / 1.6)
* Max. range = 12 bits signed = 11 bits unsigned
*/
const uint16_t expected_value
= ((1 << 11) * 1900UL) / (3300L * 1000L / 1600L);
/* Captured value for gain correction */
uint16_t captured_value;
/* DAC Output 0 Volt */
main_dac_output(0);
/* Capture value for 0 Volt */
adc_wait_for_interrupt_flag(&ADCA, ADC_CH0);
adc_wait_for_interrupt_flag(&ADCA, ADC_CH0);
offset_correction = adc_get_unsigned_result(&ADCA, ADC_CH0);
/* Enable offset correction */
adcch_read_configuration(&ADCA, ADC_CH0, &adcch_conf);
adcch_enable_correction(&adcch_conf, offset_correction, 1, 1);
adcch_write_configuration(&ADCA, ADC_CH0, &adcch_conf);
/* DAC Output 1.9 Volts */
main_dac_output(1900);
/* Capture value for 1.9 Volts */
adc_wait_for_interrupt_flag(&ADCA, ADC_CH0);
adc_wait_for_interrupt_flag(&ADCA, ADC_CH0);
captured_value = adc_get_unsigned_result(&ADCA, ADC_CH0);
/* Enable offset & gain correction */
adcch_enable_correction(&adcch_conf, offset_correction, expected_value,
captured_value);
adcch_write_configuration(&ADCA, ADC_CH0, &adcch_conf);
/* Check values */
for (volt_output = -CONV_MAX_VOLTAGE;
volt_output <= CONV_MAX_VOLTAGE;
volt_output += CONV_VOLTAGE_STEP) {
main_dac_output(volt_output);
volt_input = main_adc_input();
if (volt_output > volt_input) {
error = volt_output - volt_input;
} else {
error = volt_input - volt_output;
}
test_assert_true(test,
error < CONF_TEST_ACCEPT_DELTA_CORRECTION,
"ADC result is outside acceptable range (expected %d, captured %d)",
volt_output, volt_input);
}
}
