XYZE stepper commands to motors in firmware?

[jazbaatbadalgaye]

I am going over the 3.4 dev version of the RepRap firmware and was interested in knowing how and where in the firmware are the XYZE stepper commands sent out to the corresponding motors?

[dc42]

@jazbaatbadalgaye the step commands are sent in function DDA::StepDrivers.

[jazbaatbadalgaye]

@dc42 Thanks! Also can you please explain me what is the purpose of the DDARing?

[dc42]

@jazbaatbadalgaye the DDA ring is a queue of motion commands waiting to be executed. Moves are buffered in the queue so that where possible moves can be executed after each other without requiring motion to come to a complete stop between each pair of moves.