WIP: Add support for 6 DShot outputs to the IOMCU

[mirkix]

WIP do not merge

This PR adds 6 additional DShot outputs to the IOMCU. As the result we can use up to 12 DShot outputs with i.e. a CubeBlack or other autopilots that use an IOMCU.

What will work:

• Up to 6 DShot outputs with DSHOT150 and DSHOT 300
• To timer and dma dependencies output 1,2,5,6,7,8 can be used for DShot
• DShot telemetry requests

What will not work:

• DSHOT600 and DSHOT 1200, padding must be checked
• BlHeli pass through because of the hardware that is used (only output signals are possible)

[tridge]

really nice work! Just need to solve the extra pulses puzzle

[tridge]

I've rebased this and been doing some testing. I'm getting some quite strange results. With no RC input connected it did work a few times, but when I have RC in connected I get quite a few resets of the IOMCU. I suspect it is running out of memory.
I'll do some more testing soon

[dkemxr]

I have tried a version of this on a Pixhawk (fmuv3) but I'm not seeing Dshot from the outputs. I configured a Hexa with outputs on Main 1,2,5,6,7,8 set MOT_PWM_TYPE to Dshot150, selected those channels in the BLH Mask and set Dshot150 with the Otype parameter. I'm scoping the outputs, no ESC connected and I see standaed PWM.

[mirkix]

@dkemxr Did you execute Tools/scripts/build_iofirmware.py before you compile the PR for fmuv3?

[dkemxr]

Mirko-I used a version compiled by Mark Whitehorn as I can't do that. I'll be happy to try any compiled version, I have a bench setup to test it on.