/**
* Selects the specified analog input, automatically handling any multiplexing and timing needs.
*
* @param input Analog_Input_t* The analog input to select.
* @retval none
*/
void SelectAnalogInput(Analog_Input_t* input) {
if (input != NULL ) {
if (isExternalInput(input->physicalInput)) {
SelectExternalInput(input->externalInput);
CurrentInput = input;
} else if (isInternalInput(input->physicalInput)) {
SelectInternalInput(input->internalInput);
CurrentInput = input;
} else if (input->physicalInput == EXTERNAL_OFFSET_CAL) {
SelectCalibrationInput();
CurrentInput = input;
} else {
/* ERROR */
snprintf(TOSTRING_BUFFER, sizeof(TOSTRING_BUFFER),
"[Analog Input Multiplexer] Attempted to select an input which does not exist.");
TelnetWriteErrorMessage(TOSTRING_BUFFER);
#ifdef INPUT_MULTIPLEXER_DEBUG
printf("[Analog Input Multiplexer] Attempted to select an input which does not exist.\n\r");
#endif
}
} else {
#ifdef INPUT_MULTIPLEXER_DEBUG
printf("[Analog Input Multiplexer] Attempted to select a NULL input.\n\r");
#endif
}
}
/**
* Retrieve the gain calibration value for the specified sampling parameters.
*
* @param rate ADS1256_SPS_t The sample rate to lookup for.
* @param gain ADS1256_PGA_t The gain to lookup for.
* @param buffer ADS1256_BUFFER_t The buffer setting to lookup for.
* @param temperature float The temperature value to lookup for.
* @retval The determined calibration value.
*/
uint32_t Tekdaqc_GetGainCalibration(ADS1256_SPS_t rate, ADS1256_PGA_t gain, ADS1256_BUFFER_t buffer, float temperature) {
uint8_t rate_index = 0U;
uint8_t gain_index = 0U;
uint8_t buffer_index = 0U;
ComputeTableIndices(&rate_index, &gain_index, &buffer_index, rate, gain, buffer);
uint32_t baseGain = baseGainCalibrations[rate_index][gain_index][buffer_index];
if (CALIBRATION_VALID != TRUE) {
#ifdef CALIBRATION_TABLE_DEBUG
printf("[Calibration Table] The calibration table is not valid, returning ADC calibration only (0x%" PRIX32 ").\n\r", baseGain);
#endif
return baseGain;
}
if (temperature < CAL_TEMP_LOW || temperature > CAL_TEMP_HIGH) {
/* The temperature is out of range, we will return the closest */
#ifdef CALIBRATION_TABLE_DEBUG
printf("[Calibration Table] The requested temperature %f was out of range. Minimum is %f and maximum is %f.\n\r", temperature,
CAL_TEMP_LOW, CAL_TEMP_HIGH);
#endif
snprintf(TOSTRING_BUFFER, sizeof(TOSTRING_BUFFER),
"Error fetching the gain calibration value for temperature: %f Deg C. Temperature out of range. Allowable range is %f to %f Deg C",
temperature, CAL_TEMP_LOW, CAL_TEMP_HIGH);
TelnetWriteErrorMessage(TOSTRING_BUFFER);
if (temperature < CAL_TEMP_LOW) {
temperature = CAL_TEMP_LOW;
} else {
temperature = CAL_TEMP_HIGH;
}
}
uint8_t num_temp_steps = (uint8_t) (temperature / CAL_TEMP_STEP);
float low_temp = CAL_TEMP_LOW * num_temp_steps;
float high_temp = CAL_TEMP_HIGH * num_temp_steps;
float factor = (temperature - CAL_TEMP_LOW) / CAL_TEMP_STEP;
uint32_t offset = ComputeOffset(rate, gain, buffer, low_temp); //Add one for the move to gain
uint32_t Address = CAL_DATA_START_ADDR + 4 * offset; //Multiply offset by 4 because entries are 4bytes long
uint32_t data_low = (*(__IO uint32_t*) Address);
offset = ComputeOffset(rate, gain, buffer, high_temp); //Add one for the move to gain
Address = CAL_DATA_START_ADDR + 4 * offset; //Multiply offset by 4 because entries are 4bytes long
uint32_t data_high = (*(__IO uint32_t*) Address);
return (baseGain + InterpolateValue(data_low, data_high, factor));
}
/**
* @internal
* Computes the address offset for the offset calibration value corresponding to the specified parameters.
*
* @param rate ADS1256_SPS_t The sample rate to lookup for.
* @param gain ADS1256_PGA_t The gain to lookup for.
* @param bufer ADS1256_BUFFER_t The buffer setting to lookup for.
* @param temperature float The temperature value to lookup for.
* @retval The computed address offset.
*/
static uint32_t ComputeOffset(ADS1256_SPS_t rate, ADS1256_PGA_t gain, ADS1256_BUFFER_t buffer, float temperature) {
uint32_t offset = 0;
switch (buffer) {
case ADS1256_BUFFER_ENABLED:
offset += CALIBRATION_BUFFER_OFFSET;
break;
case ADS1256_BUFFER_DISABLED:
/* No offset, do nothing */
break;
default:
snprintf(TOSTRING_BUFFER, sizeof(TOSTRING_BUFFER),
"Error computing lookup offset in calibration table for rate: %s, gain: %s, buffer: %s and temperature: %f Deg C.",
ADS1256_StringFromSPS(rate), ADS1256_StringFromPGA(gain), ADS1256_StringFromBuffer(buffer), temperature);
TelnetWriteErrorMessage(TOSTRING_BUFFER);
break;
}
return offset;
}
