How could I go about modifying the code so that I can only drive stepper motors coordinated? about core HOT 5 CLOSED

You have to get planner.c and stepper.c working by adding/substituting the needed code from (many) other files. Call plan_buffer_line() to queue motion. It will be a lot of work...

If you do not mind dragging in everything you can write a plugin for grblHAL that takes over control and calls mc_line() in motion_control.c to enqueue motion.

accelstepper is a Arduino library? If so the grblHAL codebase is not best suited as is optimized for 32 bit processors. If 8 bit support is required then IMO Grbl is a better choice. Or there might be other libraries available that is made for controlling multiple motors?

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Accelsteppers coordinated stepper movements don't have acceleration. I'm under the impression that grblHAL uses interrupts? Where is that setuped?I'm using a teensy so I found some other files for it that setups some stuff.
Maybe I should look into the plugin line but I'm not too sure about that either...

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I'm under the impression that grblHAL uses interrupts?

Yes.

Where is that setuped?

In the processor specific driver.c code.

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Would you have a starting point on taking over the controlls from grbl with a plugin? Maybe I could have a while(true) in the plugin code or would that be a bad idea?

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Would you have a starting point on taking over the controlls from grbl with a plugin?

Not really - depends on what you want to do. There are some templates available and a number of plugins that may give you some ideas.

Maybe I could have a while(true) in the plugin code or would that be a bad idea?

I think it should work as long as you are calling mc_line() to execute motions. It will block when the planner buffer is full. If you need input from the serial port for generation motion then it will be a tad more complicated.

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