/**
* Sets options for the encoder configuration register.
*
* @param[in] channel A struct containing the registers on the encoder channel
* to modify.
* @param[in] mask Array of flags that indicate which of the configure
* settings are valid.
* @param[in] settings Array of flags that indicate the configuration settings.
*/
void Encoder_Configure(MyRio_Encoder* channel, Encoder_ConfigureMask mask,
Encoder_ConfigureSettings settings)
{
NiFpga_Status status;
uint8_t cnfgValue;
/*
* Get the current value of the configure register.
*
* The returned NiFpga_Status value is stored for error checking.
*/
status = NiFpga_ReadU8(myrio_session, channel->cnfg, &cnfgValue);
/*
* Check if there was an error reading from the encoder registers.
*
* If there was an error then the rest of the function cannot complete
* correctly so print an error message to stdout and return from the
* function early.
*/
MyRio_ReturnIfNotSuccess(status,
"Could not read from the encoder configure registers!")
/*
* Clear the value of the masked bits in the configure register. This is
* done so that the correct value can be set later on.
*/
cnfgValue = cnfgValue & (~mask);
/*
* Set the value of the settings in the configure register. If the
* value to set is 0 this operation would not work unless the bit was
* previously cleared.
*/
cnfgValue = cnfgValue | settings;
/*
* Write the new value of the configure register to the device.
*/
NiFpga_MergeStatus(&status,
NiFpga_WriteU8(myrio_session, channel->cnfg, cnfgValue));
/*
* Check if there was an error writing to encoder configure registers.
*
* If there was an error then print an error message to stdout.
*/
MyRio_ReturnIfNotSuccess(status,
"Could not write to the encoder configure registers!")
}
/**
* Write a voltage value to a single channel. The channel structure must
* previously been initialized with the appropriate scale factors with
* AnalogScaling.
*
* @param[in] channel A struct containing the registers for the AIO
* channel to be written to
* @param[in] value the voltage value in volts
*/
void Aio_Write(MyRio_Aio* channel, double value)
{
NiFpga_Status status;
uint16_t valueScaled;
/*
* The value is always stored in an unsigned 16-bit register. For a signed
* channel, cast this value directly to a signed 16-bit value. Bound the
* values to their respective limits.
*/
if (channel->is_signed)
{
/*
* Scale the voltage value to the raw value.
*/
value = (value - channel->scale_offset) / channel->scale_weight;
value = (value < INT16_MIN) ? INT16_MIN : value;
value = (value > INT16_MAX) ? INT16_MAX : value;
/*
* Round the scaled value to the nearest integer.
*/
value += (value < 0.0) ? -0.5 : 0.5;
/*
* Convert the scaled value to an unsigned integer.
*/
valueScaled = (uint16_t)((int16_t)(value));
}
else
{
value = (value - channel->scale_offset) / channel->scale_weight + 0.5;
value = (value < 0) ? 0 : value;
value = (value > UINT16_MAX) ? UINT16_MAX : value;
valueScaled = (uint16_t) value;
}
/*
* Write the value to the value register.
*
* The returned NiFpga_Status value is stored for error checking.
*/
status = NiFpga_WriteU16(myrio_session, channel->val, valueScaled);
/*
* Check if there was an error writing to the write register.
*
* If there was an error then print an error message to stdout and return.
*/
MyRio_ReturnIfNotSuccess(status,
"Could not write to the AO value registers!");
/*
* Write the signal so that the FPGA will apply the new value.
*
* The returned NiFpga_Status value is stored for error checking.
*/
status = NiFpga_WriteU16(myrio_session, channel->set, 1);
/*
* Check if there was an error writing to the set register.
*
* If there was an error then print an error message to stdout.
*/
MyRio_ReturnIfNotSuccess(status, "Could not write to the AO set registers!")
}
