This sample C code demonstrates how simple accessing one or more REG-1 devices can be. There are more robust samples, complete with a user interface and error-checking available with the SDK.
'C Sample API Usage
iNewSources = PsyREGEnumerateSources();
Source = PsyREGGetSource( 0 );
bResult = PsyREGOpen( Source );
iResult = PsyREGGetBytes( Source, rgucReadBuffer, 256, FALSE );
/* OR: iResult = PsyREGGetBits( Source, rgucReadBuffer, 256, FALSE ); */
PsyREGClose( Source );