//----------------------------------------------------------------------------
//
// Function : Acquire data
//
// Description : Acquire data from board, optionally saving data to file.
//
//----------------------------------------------------------------------------
static public unsafe bool AcquireData(IntPtr boardHandle, IntPtr fftHandle, UInt32 recordLength_samples)
{
UInt32 retCode;
// TODO: Specify the number of records per DMA buffer
UInt32 recordsPerBuffer = 10;
// TODO: Specify the total number of buffers to capture
UInt32 buffersPerAcquisition = 10;
// Acquiring from a single channel
UInt32 channelMask = AlazarAPI.CHANNEL_A;
// TODO: Select if you wish to save the sample data to a file
bool saveData = false;
// TODO: Select the FFT output format
AlazarAPI.FFT_OUTPUT_FORMAT outputFormat = AlazarAPI.FFT_OUTPUT_FORMAT.FFT_OUTPUT_FORMAT_U16_LOG;
// TODO: Select the presence of NPT footers
AlazarAPI.FFT_FOOTER footer = AlazarAPI.FFT_FOOTER.FFT_FOOTER_NONE;
// Get the sample size in bits, and the on-board memory size in samples per channel
Byte bitsPerSample;
UInt32 maxSamplesPerChannel;
retCode = AlazarAPI.AlazarGetChannelInfo(
boardHandle,
&maxSamplesPerChannel,
&bitsPerSample
);
if (retCode != AlazarAPI.ApiSuccess)
{
Console.WriteLine("Error: AlazarGetChannelInfo failed -- " +
AlazarAPI.AlazarErrorToText(retCode));
return(false);
}
FileStream fileStream = null;
bool success = true;
try
{
// Create a data file if required
if (saveData)
{
fileStream = File.Create(@"data.bin");
}
// Configure the FFT
UInt32 fftLength_samples = 1;
while (fftLength_samples < recordLength_samples)
{
fftLength_samples *= 2;
}
UInt32 bytesPerOutputRecord;
retCode = AlazarAPI.AlazarFFTSetup(
fftHandle,
(UInt16)channelMask,
recordLength_samples,
fftLength_samples,
(UInt32)outputFormat,
(UInt32)footer,
0,
&bytesPerOutputRecord
);
if (retCode != AlazarAPI.ApiSuccess)
{
throw new System.Exception("Error: AlazarFFTSetup failed -- " +
AlazarAPI.AlazarErrorToText(retCode));
}
UInt32 bytesPerBuffer = bytesPerOutputRecord * recordsPerBuffer;
// Allocate memory for sample buffer
byte[] buffer = new byte[bytesPerBuffer];
// Cast byte array to short array
ByteToShortArray byteToShortArray = new ByteToShortArray();
byteToShortArray.bytes = buffer;
fixed(short *pBuffer = byteToShortArray.shorts)
{
// Configure the board to make an NPT_onFPGA_FFT acquisition
UInt32 recordsPerAcquisition = recordsPerBuffer * buffersPerAcquisition;
UInt32 admaFlags = AlazarAPI.ADMA_EXTERNAL_STARTCAPTURE | AlazarAPI.ADMA_NPT | AlazarAPI.ADMA_DSP | AlazarAPI.ADMA_FIFO_ONLY_STREAMING | AlazarAPI.ADMA_ALLOC_BUFFERS;
retCode = AlazarAPI.AlazarBeforeAsyncRead(
boardHandle,
channelMask,
0,
bytesPerOutputRecord,
recordsPerBuffer,
0x7FFFFFFF,
admaFlags
);
if (retCode != AlazarAPI.ApiSuccess)
{
throw new System.Exception("Error: AlazarBeforeAsyncRead failed -- " +
AlazarAPI.AlazarErrorToText(retCode));
}
// Arm the board to begin the acquisition
retCode = AlazarAPI.AlazarStartCapture(boardHandle);
if (retCode != AlazarAPI.ApiSuccess)
{
throw new System.Exception("Error: AlazarStartCapture failed -- " +
AlazarAPI.AlazarErrorToText(retCode));
}
// Wait for each buffer to be filled, then process the buffer
Console.WriteLine("Capturing {0} buffers ... press any key to abort",
buffersPerAcquisition);
int startTickCount = System.Environment.TickCount;
UInt32 buffersCompleted = 0;
Int64 bytesTransferred = 0;
bool done = false;
while (!done)
{
// TODO: Set a buffer timeout that is longer than the time
// required to capture all the records in one buffer.
UInt32 timeout_ms = 5000;
// Wait for a buffer to be filled by the board.
retCode = AlazarAPI.AlazarWaitNextAsyncBufferComplete(
boardHandle,
pBuffer,
bytesPerBuffer,
timeout_ms
);
if (retCode == AlazarAPI.ApiSuccess)
{
// This buffer is full, but there are more buffers in the acquisition.
}
else if (retCode == AlazarAPI.ApiTransferComplete)
{
// This buffer is full, and it's the last buffer of the acqusition.
done = true;
}
else
{
throw new System.Exception("Error: AlazarWaitNextAsyncBufferComplete failed -- " +
AlazarAPI.AlazarErrorToText(retCode));
}
buffersCompleted++;
bytesTransferred += bytesPerBuffer;
// TODO: Process sample data in this buffer.
// NOTE:
//
// While you are processing this buffer, the board is already
// filling the next available buffer(s).
//
if (saveData)
{
// Write record to file
fileStream.Write(buffer, 0, (int)bytesPerBuffer);
}
// If a key was pressed, exit the acquisition loop
if (Console.KeyAvailable == true)
{
Console.WriteLine("Aborted...");
done = true;
}
if (buffersCompleted >= buffersPerAcquisition)
{
done = true;
}
// Display progress
Console.Write("Completed {0} buffers\r", buffersCompleted);
}
// Display results
double transferTime_sec = ((double)(System.Environment.TickCount - startTickCount)) / 1000;
Console.WriteLine("Capture completed in {0:N3} sec", transferTime_sec);
UInt32 recordsTransferred = recordsPerBuffer * buffersCompleted;
double buffersPerSec;
double bytesPerSec;
double recordsPerSec;
if (transferTime_sec > 0)
{
buffersPerSec = buffersCompleted / transferTime_sec;
bytesPerSec = bytesTransferred / transferTime_sec;
recordsPerSec = recordsTransferred / transferTime_sec;
}
else
{
buffersPerSec = 0;
bytesPerSec = 0;
recordsPerSec = 0;
}
Console.WriteLine("Captured {0} buffers ({1:G4} buffers per sec)", buffersCompleted, buffersPerSec);
Console.WriteLine("Captured {0} records ({1:G4} records per sec)", recordsTransferred, recordsPerSec);
Console.WriteLine("Transferred {0} bytes ({1:G4} bytes per sec)", bytesTransferred, bytesPerSec);
}
}
catch (Exception exception)
{
Console.WriteLine(exception.ToString());
success = false;
}
finally
{
// Close the data file
if (fileStream != null)
{
fileStream.Close();
}
// Abort the acquisition
retCode = AlazarAPI.AlazarAbortAsyncRead(boardHandle);
if (retCode != AlazarAPI.ApiSuccess)
{
Console.WriteLine("Error: AlazarAbortAsyncRead failed -- " +
AlazarAPI.AlazarErrorToText(retCode));
}
}
return(success);
}