/**
* Get a scaled sample straight from the channel on this module.
*
* The value is scaled to units of Volts using the calibrated scaling data from GetLSBWeight() and GetOffset().
*
* @param analog_port_pointer Pointer to the analog port to use.
* @return A scaled sample straight from the channel on this module.
*/
float getAnalogVoltage(void* analog_port_pointer, int32_t *status) {
int16_t value = getAnalogValue(analog_port_pointer, status);
uint32_t LSBWeight = getAnalogLSBWeight(analog_port_pointer, status);
int32_t offset = getAnalogOffset(analog_port_pointer, status);
float voltage = LSBWeight * 1.0e-9 * value - offset * 1.0e-9;
return voltage;
}
/**
* Get the factory scaling offset constant.
*
* Volts = ((LSB_Weight * 1e-9) * raw) - (Offset * 1e-9)
*
* @return Offset constant.
*/
int32_t AnalogInput::GetOffset() const {
if (StatusIsFatal()) return 0;
int32_t status = 0;
int32_t offset = getAnalogOffset(m_port, &status);
wpi_setErrorWithContext(status, getHALErrorMessage(status));
return offset;
}
/**
* Get a scaled sample from the output of the oversample and average engine for the channel.
*
* The value is scaled to units of Volts using the calibrated scaling data from GetLSBWeight() and GetOffset().
* Using oversampling will cause this value to be higher resolution, but it will update more slowly.
* Using averaging will cause this value to be more stable, but it will update more slowly.
*
* @param analog_port_pointer Pointer to the analog port to use.
* @return A scaled sample from the output of the oversample and average engine for the channel.
*/
float getAnalogAverageVoltage(void* analog_port_pointer, int32_t *status) {
int32_t value = getAnalogAverageValue(analog_port_pointer, status);
uint32_t LSBWeight = getAnalogLSBWeight(analog_port_pointer, status);
int32_t offset = getAnalogOffset(analog_port_pointer, status);
uint32_t oversampleBits = getAnalogOversampleBits(analog_port_pointer, status);
float voltage = ((LSBWeight * 1.0e-9 * value) / (float)(1 << oversampleBits)) - offset * 1.0e-9;
return voltage;
}
/*
* Class: edu_wpi_first_wpilibj_hal_AnalogJNI
* Method: getAnalogOffset
* Signature: (Ljava/nio/ByteBuffer;Ljava/nio/IntBuffer;)I
*/
JNIEXPORT jint JNICALL Java_edu_wpi_first_wpilibj_hal_AnalogJNI_getAnalogOffset
(JNIEnv * env, jclass, jobject id, jobject status)
{
void ** javaId = (void**)env->GetDirectBufferAddress(id);
ANALOGJNI_LOG(logDEBUG) << "Analog Ptr = " << *javaId;
jint * statusPtr = (jint*)env->GetDirectBufferAddress(status);
jint returnValue = getAnalogOffset(*javaId, statusPtr);
ANALOGJNI_LOG(logDEBUG) << "Status = " << *statusPtr;
ANALOGJNI_LOG(logDEBUG) << "AnalogOffset = " << returnValue;
return returnValue;
}
/**
* Convert a voltage to a raw value for a specified channel.
*
* This process depends on the calibration of each channel, so the channel
* must be specified.
*
* @todo This assumes raw values. Oversampling not supported as is.
*
* @param analog_port_pointer Pointer to the analog port to use.
* @param voltage The voltage to convert.
* @return The raw value for the channel.
*/
int32_t getAnalogVoltsToValue(void* analog_port_pointer, double voltage, int32_t *status) {
if (voltage > 5.0) {
voltage = 5.0;
*status = VOLTAGE_OUT_OF_RANGE;
}
if (voltage < 0.0) {
voltage = 0.0;
*status = VOLTAGE_OUT_OF_RANGE;
}
uint32_t LSBWeight = getAnalogLSBWeight(analog_port_pointer, status);
int32_t offset = getAnalogOffset(analog_port_pointer, status);
int32_t value = (int32_t) ((voltage + offset * 1.0e-9) / (LSBWeight * 1.0e-9));
return value;
}