- most px4_io-v2 boards have a blue LED that breathes for status
- the pixhawk 2.1 (hex) re-used this blue LED for as an IMU heater (active low), but kept the same board id (so we have to detect at runtime)
- the new cubepilot boards (yellow, orange) inverted the polarity of this heater pin
- untangle the mess slightly so that things we know statically (eg cubepilot cubeorange LEDs and heater polarity) are handled at build time.
- previously an invalid decode would continue to be transferred to the FMU (at 50 Hz) and published to the rest of the system as successfully decoded new RC data
- by only publishing new successful decodes we can more effectively discard invalid data in downstream consumers
- cmake NuttX build wrapper compile in place instead of copying source tree to build directory
- slightly faster skipping necessary copying (depending on system)
- allows debugging in place
- easier to work directly in NuttX following official documentation
- simplifies overall build which should make it easier to resolve any remaining NuttX dependency issues in the build system
- the downside is switching back and forth between different builds always require rebuilding NuttX, but I think this is worth the improved developer experience
- also no longer builds px4io and bootloader in every single build, for most users these rarely change and we're wasting a lot of build time
Daniel Agar