I am using Silicon Lab's USB to RS232 bridge. With loopback on this port, I get the following error message when using "Basic Serial Write and Read.vi" from the LabView examples. The error occurs when "VISA Write.vi" executes.
Error -1073807298 occurred at VISA Write in Basic Serial Write and Read.vi
VISA: (Hex 0xBFFF003E) Could not perform operation because of I/O error.
Loopback test using Hyperterminal, MAX's VISA Test Panel and Loopback.vi was successful.
Port was set at 9600 baud, 8, N, 1 and No Flow control.
I will appreciate any suggestions to identify the problem or alternative techniques to write to the serial port.
Not all USB to serial converters are created equal. There are several USB to serial converters that ship with drivers that do not implement the entire standard Windows API for serial port. It seems that your Silicon Lab's USB to RS232 bridge driver does not implement the Flush Buffer command.
I would also be careful using that device on dual processor or hyper threaded machines. The driver might not be multiprocessor safe.
If you want a USB to serial converter that supports the full serial API and has support for multiple processors and has a Windows signed driver I would recommend the NI USB-232 dongle.
