Communicate with Digilent Nexys 3 Spartan 6

The datasheet and schematics are here:-

http://store.digilentinc.com/nexys-3-spartan-6-fpga-trainer-board-limited-time-see-nexys4-ddr/

It doesn't look as though the nexys 3 has got an old fashioned dedicated UART port. It seems to expect to use its USB ports for keyboard and mouse.

If it did have a dedicated UART port I think you'd expect to see a 9 way D type connector on the card: and the only possible contender looking at the pictures is clearly a 15 way VGA port:-

Of course you could easily include a UART design in the FPGA and use one of the General purpose I/O ports.

I think we need a lot more information if we are going to be of any help.

Thank you for your response. I relayed your information and here is new information in case it helps:

I was directed to a pdf of the manual. The board has a uart in the lower right corner. It looks like the picture that you had posted is one of the examples given on the digilent website along with another version of the picture I'm attaching below. Not sure why the image digilent included was there, but in any case, below is a picture of the board in question.

https://forums.xilinx.com/xlnx/attachments/xlnx/EDK/22262/1/Nexys3_rm.pdf

It seems that the issue is that the Labview code is done, but there is a need for code (vhdl) that will take the rx and tx data that is processed by the board in parallel and convert it to serial. I am not familiar with the data coming off a parallel vs serial port to be able to talk intelligently about this, but essentially what my friend is looking for is sample code that would give examples of how to set up the code so that his code can call the individual outputs from the parallel port (hope this makes sense).

I did find a tutorial online that has an RS232 implementation using vhdl and have passed this on to my friend as well. The board is different but maybe is a related process. https://www.youtube.com/watch?v=T9VbBI3foGQ

Hope this helps.

The connector labelled USB UART is a USB port: it is connected to an RS232 to USB converter IC

So although internally the board can be using a UART/RS232 port, externally the interface is USB.

This is almost certainly the way your friend is trying to use it, but he won't see any RS232 like signals on J13.

He can probe the internal RS232 signals (MCU-Tx, MCU-Rx, RTS etc.) with a scope. They will look like RS232 signals but will be at the lower internal logic levels.

The board almost certainly offers other ways to monitor/debug what's going on without resorting to a scope, but, ultimately that's the only way to see what's really happening.

EDIT: I see that Solar Eagle has already pointed you in the same direction (GA).

Maybe something here can help...

https://en.wikibooks.org/wiki/Serial_Programming/RS-232_Connections

http://www.ftdichip.com/Products/ICs/FT232R.htm