- no longer start sercon or mavlink usb by default
- on USB connection (VBUS) monitor serial USB at low rate and start Mavlink if there's a HEARTBEAT or nshterm on 3 consecutive carriage returns
- the mavlink USB instance is automatically stopped and serdis executed if USB is disconnected
- skipping Mavlink USB (and sercon) saves a considerable amount of memory on older boards
Reduces CPU load by almost 1.5% @ 2khz on F4 and F7.
This changes the motor ordering on boards where the timer ordering does
not match the order of the timer usage in the channels defintion.
Only omnibus f4sd is affected.
- currently the main change is that it reduces the max number of ORB multi instances to 4, but usage will be expanded as needed
- limits number of EKF2 multi instances to 2.
- enabled on all cortex m4 boards
- skip avionics rail voltage check when USB connected
- skip forced reboot on USB disconnect if circuit breaker set
- avionics voltage preflight check don't silently fail if system_power unavailble
- explicitly set supply check circuit breaker (CBRK_SUPPLY_CHK)
- always check with state machine before reboot/shutdown
- respect BOARD_HAS_POWER_CONTROL (shutdown from command, low battery, power button)
- px4_shutdown_request add optional delay and always execute from HPWORK
- px4_shutdown_request split out px4_reboot_request
- increase stack sizes to run cleanly under stackcheck
- this is likely overkill for most boards, but using stackcheck to set our minimum ensures we have a very safe margin on regular builds and it's something we can currently afford
- remove holybro_durandal-v1_stackcheck from test rack (there's only one unit)