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.


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