RPI4 Raspbian 64 bit & LinuxCNC

Cant do this anymore bye all wrote:

I was under the impression that if a deb package was built against a certain library dev package that the library package was automatically included as a dependency.

Only if the dependencies are listed in the debian control file by the developer of the .deb file
I'm not sure if dependencies can be specified for specific architectures
I think I did a bit of a package search on the debian site and decided to add gpiod-dev to the builder,  but left gpiod out. I'll add it back in.
There are probably a few more that will come to light.

gpioinfo gives output i can read and write GPIO pins in terminal.



Can you please show example ?

rodw wrote:

Only if the dependencies are listed in the debian control file by the developer of the .deb file

libgpiod-dev has libgpiod2 as a dependency:
packages.debian.org/stable/libdevel/libgpiod-dev
But that does not appear to have a dependency on gpiod.
This might not be a problem, as I think that goiod is just the package that includes the tools (like gpioinfo) and isn't necessary for the library code to work.

Donno wrote:

Code:

Can you please show example ?

Base thread gave me error so i used servo thread :

GPIO working as expected



sorry for dog noises.

Verry cool!
If you installed gpiod, can you remove it and retest?
sudo apt remove gpiod
I was going to add gpiod to the image but if it works without it there is no need and the last image can be a final for a while.
We will leave the installer on 2.10 branch for now. Hopefully,  Andy can backport the driver to 2.9 branch before 2.9 is released.

I did not install gpiod.

I think you'd have to spend some time working on latency to run a base thread to run steppers from the GPIO.

Maybe with a decent sd card, 3 cores isolated and a base thread of 30k to 40k you may have luck.

I did my testing on a Pi400 with a 10kHz base thread. With the reset function you can still get to 750rpm with 4x microstepping on a 200 step motor.

andypugh wrote:

I did my testing on a Pi400 with a 10kHz base thread. With the reset function you can still get to 750rpm with 4x microstepping on a 200 step motor.

I don't understand why people insist on using a base thread on the Pi. It has a 54 Mhz timer frequency so that means  using a simple square wave, the maximum frequency  is 27 Mhz. We should be driving it like a Mesa stepgen.

I have run steppers on an Arduino this way.   To program a pulse with say 10 usec to write to a port and the same for the time for the end of a pulse, (total 30 usec), you should be able to get up to 33 kHz without a base thread. (if my maths is right) Which gives you about 1000 rpm on 10 x microstepping. MOst motors give up at 750 rpm