void ImpedanceMeasurement()
{
var actualImpedanceFreq = 0.0;
var sampleRate = evalBoard.GetSampleRate();
var chipRegisters = new Rhd2000Registers(sampleRate);
var ledSequence = LedSequence();
ledSequence.MoveNext();
// Create a command list for the AuxCmd1 slot.
var commandList = new List <int>();
var sequenceLength = chipRegisters.CreateCommandListZcheckDac(commandList, actualImpedanceFreq, 128.0);
evalBoard.UploadCommandList(commandList, AuxCmdSlot.AuxCmd1, 1);
evalBoard.SelectAuxCommandLength(AuxCmdSlot.AuxCmd1, 0, sequenceLength - 1);
evalBoard.SelectAuxCommandBank(BoardPort.PortA, AuxCmdSlot.AuxCmd1, 1);
evalBoard.SelectAuxCommandBank(BoardPort.PortB, AuxCmdSlot.AuxCmd1, 1);
evalBoard.SelectAuxCommandBank(BoardPort.PortC, AuxCmdSlot.AuxCmd1, 1);
evalBoard.SelectAuxCommandBank(BoardPort.PortD, AuxCmdSlot.AuxCmd1, 1);
// Select number of periods to measure impedance over
int numPeriods = (int)Math.Round(0.020 * actualImpedanceFreq); // Test each channel for at least 20 msec...
if (numPeriods < 5)
{
numPeriods = 5; // ...but always measure across no fewer than 5 complete periods
}
double period = sampleRate / actualImpedanceFreq;
int numBlocks = (int)Math.Ceiling((numPeriods + 2.0) * period / 60.0); // + 2 periods to give time to settle initially
if (numBlocks < 2)
{
numBlocks = 2; // need first block for command to switch channels to take effect.
}
chipRegisters.SetDspCutoffFreq(DspCutoffFrequency);
chipRegisters.SetLowerBandwidth(LowerBandwidth);
chipRegisters.SetUpperBandwidth(UpperBandwidth);
chipRegisters.EnableDsp(DspEnabled);
chipRegisters.EnableZcheck(true);
sequenceLength = chipRegisters.CreateCommandListRegisterConfig(commandList, false);
// Upload version with no ADC calibration to AuxCmd3 RAM Bank 1.
evalBoard.UploadCommandList(commandList, AuxCmdSlot.AuxCmd3, 3);
evalBoard.SelectAuxCommandLength(AuxCmdSlot.AuxCmd3, 0, sequenceLength - 1);
evalBoard.SelectAuxCommandBank(BoardPort.PortA, AuxCmdSlot.AuxCmd3, 3);
evalBoard.SelectAuxCommandBank(BoardPort.PortB, AuxCmdSlot.AuxCmd3, 3);
evalBoard.SelectAuxCommandBank(BoardPort.PortC, AuxCmdSlot.AuxCmd3, 3);
evalBoard.SelectAuxCommandBank(BoardPort.PortD, AuxCmdSlot.AuxCmd3, 3);
evalBoard.SetContinuousRunMode(false);
evalBoard.SetMaxTimeStep((uint)samplesPerBlock * (uint)numBlocks);
// Create matrices of doubles of size (numStreams x 32 x 3) to store complex amplitudes
// of all amplifier channels (32 on each data stream) at three different Cseries values.
var numChannels = 32;
var numStreams = evalBoard.GetNumEnabledDataStreams();
var measuredMagnitude = new double[numStreams][, ];
var measuredPhase = new double[numStreams][, ];
for (int i = 0; i < numStreams; i++)
{
measuredMagnitude[i] = new double[numChannels, 3];
measuredPhase[i] = new double[numChannels, 3];
}
// We execute three complete electrode impedance measurements: one each with
// Cseries set to 0.1 pF, 1 pF, and 10 pF. Then we select the best measurement
// for each channel so that we achieve a wide impedance measurement range.
Queue <Rhd2000DataBlock> dataQueue = new Queue <Rhd2000DataBlock>();
for (int capRange = 0; capRange < 3; capRange++)
{
double cSeries;
switch (capRange)
{
case 0:
chipRegisters.SetZcheckScale(ZcheckCs.ZcheckCs100fF);
cSeries = 0.1e-12;
break;
case 1:
chipRegisters.SetZcheckScale(ZcheckCs.ZcheckCs1pF);
cSeries = 1.0e-12;
break;
default:
chipRegisters.SetZcheckScale(ZcheckCs.ZcheckCs10pF);
cSeries = 10.0e-12;
break;
}
// Check all 32 channels across all active data streams.
for (int channel = 0; channel < numChannels; channel++)
{
chipRegisters.SetZcheckChannel(channel);
sequenceLength = chipRegisters.CreateCommandListRegisterConfig(commandList, false);
// Upload version with no ADC calibration to AuxCmd3 RAM Bank 1.
evalBoard.UploadCommandList(commandList, AuxCmdSlot.AuxCmd3, 3);
// Start SPI interface and wait for command to complete.
evalBoard.Run();
while (evalBoard.IsRunning())
{
Thread.Sleep(0);
}
evalBoard.ReadDataBlocks(numBlocks, dataQueue);
MeasureComplexAmplitude(measuredMagnitude, measuredPhase, null, capRange, channel, numStreams, numBlocks, sampleRate, actualImpedanceFreq, numPeriods);
// Advance LED display
ledSequence.MoveNext();
}
}
evalBoard.SetContinuousRunMode(false);
evalBoard.SetMaxTimeStep(0);
evalBoard.Flush();
// Switch back to flatline
evalBoard.SelectAuxCommandBank(BoardPort.PortA, AuxCmdSlot.AuxCmd1, 0);
evalBoard.SelectAuxCommandBank(BoardPort.PortB, AuxCmdSlot.AuxCmd1, 0);
evalBoard.SelectAuxCommandBank(BoardPort.PortC, AuxCmdSlot.AuxCmd1, 0);
evalBoard.SelectAuxCommandBank(BoardPort.PortD, AuxCmdSlot.AuxCmd1, 0);
evalBoard.SelectAuxCommandLength(AuxCmdSlot.AuxCmd1, 0, 1);
UpdateRegisterConfiguration(fastSettle: false);
// Turn off LED.
ledSequence.Dispose();
}