How to modify the pin of joint.0.free-pos-cmd?

• How to modify the pin of joint.0.free-pos-cmd? My purpose is to control motor movement only by modifying the pin

This is an output, you cannot modify that pin.

I will modify the linuxcnc source code, and build, to change the pin to IO type, my setp still can't change, my purpose is to just set the pin to make the electric power.

Hello, can we make friends and communicate with each other to learn linuxcnc? I come from China, do you have the contact information

Another factory, nice.
There are plenty of pins you can use to do pretty much everything with LinuxCNC so no need to go that deep.
There are digital and analog inputs and outputs for use inside LinuxCNC and the same can be used for controlling other stuff, like a motor.
Open hal show, on the left side you have all the active pins.
It is hard to help you when you do not give us more info.

961377074@qq.com wrote:

• How to modify the pin of joint.0.free-pos-cmd? My purpose is to control motor movement only by modifying the pin

Not knowing the exact purpose you are after, I think hal pin you probably should be using would be the input pin "joint.N.posthome-cmd" (where N=the joint number).

(how ever that pin is only exposed on extra joints not assigned to an axis.)