Uart

GNU Radio
1

Hi all.

I am using the USRP and need to receive the output from the FPGA over
pins on the BasicRX board rather than through USB. I need to send these
signals to another FPGA board I am using on which I am running a Java
processor. I’d like to avoid going via USB as I do not have a USB
interface on this second board. I understand that the FPGA already sends
the output signal from the FPGA over 16 pins on the RX board - I’m
guessing that this is the I/Q complex number generated by the FPGA.
However, because of the different clocks on the 2 boards, I need some
sort of handshaking protocol. I therefore decided that I’ll try to send
the signals over RS232.

I notice that there is an RS232 on the BasicRX board but I understand
from the schematics that this is not connected to the FPGA but to the
BasicTX board. I don’t understand why this is so. Am I correct in
saying that there is no UART core on the FPGA sending the signal to the
two pins on the BasicRX board?

I guess I could put a UART core on the USRP FPGA myself and output the
RX and TX signals on a pair of pins. Has anyone attempted to do this
before.

Any help would be much appreciated.

Thanks.

Andrew Borg

2

Andrew,

We have never used the RS232 stuff, so there is no code for it right
now.

Samples are not currently sent to the digital IO pins, but you could
modify the FPGA code to do that.

Matt

Andrew Borg wrote:

need some sort of handshaking protocol. I therefore decided that I’ll
try to send the signals over RS232.

I notice that there is an RS232 on the BasicRX board but I understand
from the schematics that this is not connected to the FPGA but to the
BasicTX board. I don’t understand why this is so. Am I correct in
saying that there is no UART core on the FPGA sending the signal to
the two pins on the BasicRX board?