Maurizio, On Wed, Aug 5, 2015 at 7:49 AM, Maurizio Crozzoli <maurizio.crozz...@telecomitalia.it> wrote: > Hi Martin or others who can support me, > I have a problem which is similar as Frank's: I have an E310 and I want to > receive a and external trigger on a pin which starts an acquisition process > of a burst of samples from the radio source.
In the default FPGA image the GPIO pins are wired up to ATR pins that are connected to the radio0. https://github.com/EttusResearch/fpga/blob/master/usrp3/top/e300/e300.v#L112 https://github.com/EttusResearch/fpga/blob/master/usrp3/top/e300/e300.v#L375 https://github.com/EttusResearch/fpga/blob/master/usrp3/top/e300/e300.v#L659 https://github.com/EttusResearch/fpga/blob/master/usrp3/top/e300/e300_core.v#L304 would be your places to start. If you want to use our GPIO API take a look at: http://files.ettus.com/manual/page_gpio_api.html > > Stated that I have to remove the box around the E310 to have access to the > GPIO ports (not a problem!), according to what I have read so far in this > thread, no way to reach my goal but using C++ (no GRC!). Not an easy task > for me but I do hope I can do it. > > What I need you support about is related to the right approach I should > follow. I would think that I should write a "while" loop which runs in ARM > processors where one on the available GPIO port is constantly monitored: > when the trigger is detected the acquisition process of a burst of samples > from the radio source is started and, once it has been completed, the flow > goes back to the GPIO port monitoring. You could either fork of a thread to monitor the ports through the UHD API, or rewire stuff in the FPGA (as pointed out above) to use the Zynq's GPIO_I signals in the FPGA. You could then use the default kernel sysfs GPIO API to use GPIO interrupts. places to start investigating are: https://www.kernel.org/doc/Documentation/gpio/sysfs.txt http://elinux.org/GPIO#GPIO_interrupts_from_user_space maybe there are python bindings available? > > Is there any example code I be inspired from? OF course I have to study what > can be found in the manual page "The E3x0/X3x0 Front Panel GPIO", but, > together with the suggested gpio.cpp example under UHD, it looks like there > is more emphasis on the ATR mechanism, which - I think - has nothing to do > with the problem I have to solve. That is true, see the above links. Depending on latency requirements, and your input signal, the ATR API might not be what you need. > > Martin or others, could you please comment on my problem? > > TIA! > > BR, > Maurizio. > > PS If you think that, according to what I have understood so far, I will > need to use RFNoC in order to cope with the sampling speed constraints of > the acquisition process of a burst of samples from the radio source, you > might well understand how much I need your help, and not just for this > post... Just for the GPIO part no requirement of using RFNOC. > > > > -- > View this message in context: > http://gnuradio.4.n7.nabble.com/Front-Panel-GPIO-on-Ettus-X310-tp53979p55274.html > Sent from the GnuRadio mailing list archive at Nabble.com. > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio Happy hacking, Moritz _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
