How can I get 2 XBee S1 RFTXs to talk to 2 Nexys2 FPGA boards with UART?

How can I get 2 XBee S1 modules to communicate with each other not using a laptop just using 2 FPGA boards through UART?

I can get them both talking with the Grove boards both attached to a computer.

However my task is to get 2 XBee modules transmitting data between 2 Digilent Nexys2 FPGA boards. I have setup all the UART vhdl code for transmitting just between the DOUT, DIN pins supplying 3.3V and ground to the appropriate pins. I am just trying to transmit a hex 55 from one module to the other. So I have put a scope on my DIN pin and I can see the transition showing hex 55, but I can’t get the other XBee S1 device that I currently have hooked up to my laptop to receive the hex 55 data using the XCTU software? I can search the remote devices and find the XBee attached to my FPGA board, but it just says “Could Not Initialize device” Any suggestions? I mean this seems like it should be straight forward I just need to transmit one byte from one board to the other board. Any suggestions?


If you connect the XBee to the Grove board and then run test wires from the Groves TX and Rx test points to your FPGA boards Tx and Rx lines does it work?