Ardupilot Mega or "APM" is an open source autopilot system. It allows the user to turn any fixed wing, rotary wing, or multi-rotor vehicle (even boats and cars) into a fully autonomous vehicle, capable of performing a wide range of tasks even programmed GPS missions with waypoints (with the optional GPS module).

APM2.8 flight controller fixes some glitches in APM 2.52 and add some new features.

1. Replace the (not used/redundant) 1.0mm 6p GPS port with df13-4P I2C external compass port, putting the GPS and external compass ports next to each other.
2. Multifunction MUX port added in the old I2C port location, this lets users select an output from the bonding pad (Uart0, Uart2, I2C, OSD “default is OSD”. This new layout makes data transmission more stable with an isolation resistance.
3. Replace the TP79133 with LP2985-3.3. the max voltage reaches 16V, this increases the reliability and reduce the probability of Bad Gyro health.
4. External Compass enable/disable jumper added, verses having to cut a trace wire.
5. Add a 47 uf tantalum capacitor which increases the stability of the power supplying.
6. 3.3V and 5V Dataflash/Flashrom swapped trace problem corrected to the AT45DB161.

NOTE: When connecting to USB, do NOT have anything else connected to the board nor Do not connect any devices such as a radio receiver, MinimOSD, GPS, etc while the APM is powered especially while powered only through the USB cable. Doing so could damage the board, this is now minimized with the SMD 3.3V regulator MOD, but best to play it safe and provide the addtional external power, and no connecting anything while powered.