🚧 PFW-1480 MMU: Add support for the M command

[gudnimg]

Important

This PR is on hold until a decision is made whether or not supporting the M command makes sense. The PR is ready for merge otherwise. If merged, this will need to be added to the MK4 as well.

The M command is used to change the TMC2130
motor modes between Stealth and Normal mode.

Note: MMU FW >3.0.0 is required since the current FW does not process the 'M' on the protocol level. To test, you should see the below in the serial logs:

echo:MMU2:>M1*e.      ; M1 means changing from Stealth to Normal, M0 would be opposite
echo:MMU2:<M1 A*c1.   ; Command accepted
echo:MMU2:>Q0*ea.     ; Query request
echo:MMU2:<M1 F0*d7.  ; Command finished 

Change in memory:
Flash: +76 bytes
SRAM: 0 bytes

[DRracer]

👍 we'll decide what to do with the stealth/normal mode after tests (hopefully we can remove the switch once for all)

[DRracer]

marked as 🚧 : waiting for the test before we decide what to do with the Stealth/Normal mode switching

[gudnimg]

Rebased to resolve merge conflict

[3d-gussner]

@DRracer any update?

[gudnimg]

Rebased to sync with MK3 branch

[github-actions]

All values in bytes. Δ Delta to base

Target	ΔFlash	ΔSRAM	Used Flash	Used SRAM	Free Flash	Free SRAM
MK3S_MULTILANG	106	0	246840	5656	7112	2536
MK3_MULTILANG	106	0	246130	5663	7822	2529

[gudnimg]

Interesting, flash usage has increased by 30 bytes 🤔

[3d-gussner]

@DRracer @gudnimg Can this be merged ? If so please remove 🚧

[gudnimg]

@DRracer @gudnimg Can this be merged ? If so please remove 🚧

No, I added 🚧 until internal testing is done. Testing should find out if there is any benefit in having Stealth mode vs Normal mode switching on new MMU. There isnt as much difference now with the new firmware, but it should be tested/verified.

Maybe @DRracer knows more?

[gudnimg]

Rebased to sync with MK3 branch

More changes are coming and back to draft

[gudnimg]

Rebased to sync with MK3 branch (96 commits)

[3d-gussner]

@DRracer Please have a look at this one again.