Hi Carel,
no, with the stock FPGA image you can not trigger on an external pulse
on GPIO etc.
However, the X310 supports timed commands, so you can set a command time
(sample clock accurately) for when a transmission should take place.
There's two workarounds I can think of:
a) the cleaner one would be getting to know RF NoC, which is Ettus'
architecture for flexible FPGA images. That would allow you to "drop in"
a signal generation/conditional pass-through block in your TX chain, and
trigger that on any FPGA signal. [1]
b) I've never tried this, but in theory, you could specify a command
time somewhere in the future, issue a streaming command[2] and set the
device time using set_time_next_pps on a pulse on the PPS input. I'd
consider that a hack, and I'm not quite sure it won't have undesirable
side effects.
All in all, maybe there's a more elegant solution to your problem. Could
you explain a bit more about your application.
Greetings,
Marcus
[1] https://github.com/EttusResearch/uhd/wiki/RFNoC:--Specification
[2] have a look at the tx_timed_samples example,
https://github.com/EttusResearch/uhd/blob/master/host/examples/tx_timed_samples.cpp
On 03/12/2015 11:39 AM, Carel Combrink via USRP-users wrote:
Hi Carel,
no, with the stock FPGA image you can not trigger on an external pulse
on GPIO etc.
However, the X310 supports timed commands, so you can set a command time
(sample clock accurately) for when a transmission should take place.
There's two workarounds I can think of:
a) the cleaner one would be getting to know RF NoC, which is Ettus'
architecture for flexible FPGA images. That would allow you to "drop in"
a signal generation/conditional pass-through block in your TX chain, and
trigger that on any FPGA signal. [1]
b) I've never tried this, but in theory, you could specify a command
time somewhere in the future, issue a streaming command[2] and set the
device time using set_time_next_pps on a pulse on the PPS input. I'd
consider that a hack, and I'm not quite sure it won't have undesirable
side effects.
All in all, maybe there's a more elegant solution to your problem. Could
you explain a bit more about your application.
Greetings,
Marcus
[1] https://github.com/EttusResearch/uhd/wiki/RFNoC:--Specification
[2] have a look at the tx_timed_samples example,
https://github.com/EttusResearch/uhd/blob/master/host/examples/tx_timed_samples.cpp
On 03/12/2015 11:39 AM, Carel Combrink via USRP-users wrote:
> Hi,
>
> Is it possible to use the X310 in a "Triggered" mode?
>
> The idea would be to provide the X310 with a buffer of data and then
> only transmit that data when an external trigger is received. I am
> assuming that one would use the GPIO port on the module but not sure
> if this is possible using the current drivers?
>
> Regards,
>
>
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