USRP2 with Basic Tx Daugther board io_tx pins monitoring

GNU Radio
#1

Hi,

I want to monitor the I and Q samples being send over to the AD9777 DAC
(channel 1). I’ve noticed on the USRP2 schematic that the FPGA provides
io_tx[0:15] pins which are routed on the daughter board for probing (I
use the Basic Tx daugther board). Now, when I run the tx_samples app
example to transmit sample (using a file read continuously) I get the
signal to the sma connector alright but if I probe the io_tx pins, I get
nothing.

The main question will be, is it possible for these pins to provide the
same values send to the DAC ? Is there a special configuration or
command that needs to be send to the FPGA to make these pins do what I
want or something else needs to be done ?

Thanks,
Leonard

–
Lonard Marziliano, Research Engineer

Communications Research Centre Canada (CRC)
3701 Carling, Ottawa, CANADA K2H 8S2
Tel: (613) 993-0578
Fax: (613) 990-0316
http://www.crc.gc.ca

#2

On 03/14/2011 08:14 AM, Leonard Marziliano wrote:

The main question will be, is it possible for these pins to provide the
same values send to the DAC ? Is there a special configuration or
command that needs to be send to the FPGA to make these pins do what I
want or something else needs to be done ?

You would need to modify the FPGA code to send the DAC signal to those
pins, which are normally used for daughterboard control.

Matt