[USRP-users] using GPIO output to trigger external RF switches

Jeff S e070832 at hotmail.com
Tue Jan 14 06:58:15 EST 2020


I am looking at GPIO right now as well.  As to your question #2 on examples, I compiled and am able to run the example I found in the UHD software:


I am able to set individual data lines to experiment with (and eventually use as a roadmap for my development) using commands like:

./gpio --dwell 0 --bitbang --ddr 0x00ff --out 0x0055

which I verified works using a logic analyzer.  I eventually want to try to create a keying loop, but that may take some FPGA control (?).


From: USRP-users <usrp-users-bounces at lists.ettus.com> on behalf of Thomas Harder via USRP-users <usrp-users at lists.ettus.com>
Sent: Tuesday, January 14, 2020 5:07 AM
To: usrp-users at lists.ettus.com <usrp-users at lists.ettus.com>
Subject: [USRP-users] using GPIO output to trigger external RF switches


I am continuously transmitting a waveform with several RF with 200MSPS with my USRP X310 (modified code on the basis of “tx_samples_from_file.cpp” with a waveform in a .dat file). I would like to get a trigger signal from the USRP when it is changing the tx- frequency which I set in my .dat file.

Could the GPIO deliver this trigger without changing the image?

I am using the SRAM image with UHD 3.14.1

A second question is concerning the GPIO example on https://files.ettus.com/manual/page_gpio_api.html.

I copied and paced it in the “tx_waveforms” example just changing the usrp device handle to “usrp” but when I compiled it and started tx, I couldn’t measure any tension on PIN 4 and 6 as defined in the example. Are there more examples how to program the GPIO?

Thank you,

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