08-10-2004 03:30 AM
08-10-2004 08:11 AM
04-03-2007 05:05 PM
I am trying to implement RS422 using the FPGA on a NI cRIO 9401. I modified the FPGA Serial Example mentioned in this post. Using a custom PCB board designed in house we take the TTL serial output and input from the cRIO module and translated into differential 5V RS422.
If I loop back the transmit and receive on the PCB board I can send and receive a text message ok.
But when I try to connect the PCB board to PCI-422 card by connecting the transmit positive to the receive positive and transmit minus to the receive minus, the text I read back is incorrect and sometimes looks like nonprintable characters. I checked the pulses that both ends generate with an oscilloscope and they look similar.
Do you have any suggestions?
Regards,
Russell
04-05-2007 02:11 PM