Assuming t_high is a uhd::time_spec_t that marks the start time of your HIGH state, simply do
auto t_low = t_high + 1e-6; and then use t_low for your second timed command: usrp->set_command_time(t_high); usrp->set_gpio_attr(/* set your pin high */); usrp->set_command_time(t_low); usrp->set_gpio_attr(/* set your pin low */); --M On Mon, Feb 24, 2025 at 9:45 AM <kavin...@atindriya.co.in> wrote: > Hi, > What is the minimum time to toggle the GPIO pin? > I want to make the GPIO pin high for 1microsecond and low for > 1milliseconds. How i achieve this through code? > > > Thanks. > > > > On 2025-02-24 01:57, Martin Braun wrote: > > You don't specify a delay, you send one timed command to make the pin > > go HIGH, and another timed command to make it go LOW. And the two > > command-times should be "your delay" apart. > > > > This may help: > > > https://www.youtube.com/watch?v=ppD06ZETnek&t=75s&pp=ygUPZ3Jjb24gdXNycCBncGlv > > > > --M > > > > On Sat, Feb 22, 2025 at 12:12 PM <kavin...@atindriya.co.in> wrote: > > > >> Hi, > >> How to give the delay in > >> uhd_usrp_set_command_time(uhd_usrp_handle > >> h,int64_t full_secs,double frac_secs,size_t mboard) function? > >> > >> On 2025-02-22 00:10, Marcus D. Leech wrote: > >>> On 21/02/2025 23:56, kavin...@atindriya.co.in wrote: > >>>> Hi, > >>>> Can I use usleep(1) or any other technique is there for GPIO . > >>>> > >>> You might be able to use timed commands: > >>> > >>> > >> > > https://files.ettus.com/manual/page_timedcmds.html#timedcmds_gen_cmds > >>> > >>> But since usleep() cannot guarantee any kind of maximum period > >> that > >>> your process will go to sleep, it is an unreliable > >>> method when precision and repeatable timing of ANY kind of > >> "doing > >>> stuff with external hardware" is required. Even if > >>> usleep() at microsecond-scale intervals *WAS* reliable and > >>> repeatable, there's no guarantee about all the *other* things > >>> that are required to launch a command over a > >> latency-not-guaranteed > >>> bus to the external hardware, including kernel-layer > >>> USB drivers, etc, etc. > >>> > >>> > >>>> > >>>> On 2025-02-21 23:37, Marcus D. Leech wrote: > >>>>> On 21/02/2025 23:22, kavin...@atindriya.co.in wrote: > >>>>>> Hi, > >>>>>> Thanks for answering. > >>>>>> Can you explain me clearly? > >>>>>> > >>>>>> Thanks. > >>>>> I'd suggest, at a minimum, looking at the MAN page for usleep(). > >>>>> > >>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>>> On 2025-02-21 23:11, Marcus D. Leech wrote: > >>>>>>> On 21/02/2025 23:05, kavin...@atindriya.co.in wrote: > >>>>>>>> Hi, > >>>>>>>> In USRP B205mini-i I am able to access the GPIO Pin. I > >> have to > >>>>>>>> create a Pulse in the GPIO pin. I want to make high the gpio > >> pin > >>>>>>>> for 1microsecond and low for 999microseconds. How to achieve > >> this > >>>>>>>> timings through coding. Can you give me the solution for > >> this? > >>>>>>>> > >>>>>>>> In coding after making high I am giving usleep(1) function > >> but > >>>>>>>> when I am check in the oscilloscope it is showing > >> 64microseconds. > >>>>>>>> How? > >>>>>>>> > >>>>>>>> > >>>>>>> Because an application-land program executing on an ordinary > >>>>>>> general-purpose operating system is unlikely to be able to > >>>>>>> achieve repeatable, 1usec-scale timing. This has nothing to > >> do, > >>>>>>> per se, with UHD or USRPs, but rather, to understanding > >>>>>>> how applications execute in a general-purpose operating > >> system > >>>>>>> that isn't ruthlessly optimized for "hard" real-time tasks. > >>>>>>> > >>>>>>> > >>>>>>> _______________________________________________ > >>>>>>> USRP-users mailing list -- usrp-users@lists.ettus.com > >>>>>>> To unsubscribe send an email to > >> usrp-users-le...@lists.ettus.com > >>>>> _______________________________________________ > >>>>> USRP-users mailing list -- usrp-users@lists.ettus.com > >>>>> To unsubscribe send an email to usrp-users-le...@lists.ettus.com > >>> _______________________________________________ > >>> USRP-users mailing list -- usrp-users@lists.ettus.com > >>> To unsubscribe send an email to usrp-users-le...@lists.ettus.com > >> _______________________________________________ > >> USRP-users mailing list -- usrp-users@lists.ettus.com > >> To unsubscribe send an email to usrp-users-le...@lists.ettus.com > > _______________________________________________ > > USRP-users mailing list -- usrp-users@lists.ettus.com > > To unsubscribe send an email to usrp-users-le...@lists.ettus.com >
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