Copter: Internal errors (0x4000)

[JustCurious8]

Bug report

Issue details Was testing HERE+ RTK GPS setup on 5" quadcopter running arducopter v4.0.4 on omnibusf4pro, so i left the drone outside for more than 1 hour to see the status of RTK GPS. Green LED was blinking in the starting and i didn't expected any change of color of LED status, i was not keeping an eye throughout that period, so after around 1 hours and 30 minutes, when i come back to see the status then i saw yellow LED blinking, i connected the drone to mission planner and found this error PreArm: Internal errors (0x4000) on HUD.

This is the 4th different kind of internal error which i have seen now in last 1 month, i had log_diarm enabled, but i doubt if anything can be confirmed from the log and similar to its other internal errors brother, this one also not reproducible and went away after reboot.

Version ArduCopter v4.0.4

Platform [ ] All [ ] AntennaTracker [ * ] Copter [ ] Plane [ ] Rover [ ] Submarine

Airframe type Quad-X

Hardware type Omnibusf4pro

Logs https://drive.google.com/file/d/1GHETwCll1ou7_h-SX5gj8PsMFr4NrLtk/view?usp=sharing

[leonisflying]

I ran into same problem. I found it inevitably comes out when I upload over 305 waypoints. My guess, it's a kind of memory overflow. My fc is a Matek f405wing, planning to order a matek f765wing which has bigger RAM & flash, so I can find out if it's a memory issue.

[muramura]

If it's due to a lack of free memory space, then I think it would be better to implement a feature that monitors the free memory space and triggers a failsafe if it continues to decrease.

[JustCurious8]

in the context of free memory space, i have another issue, i have disabled smartRTL and terrain features on omnibusf4pro, after disabling these features i got around 55Kb of free memory from total 192Kb memory on omnibusf4pro board, so i thought to do some experiments with that free memory as i thought memory is a kind of resource which can be good to have if you wanna try some firmware customizations, but in case where i use this free memory space to create string buffers in heap or in static memory space then there seems some issues if i use more than 16-17Kb of free 55Kb memory, using more than 17Kb of 55Kb memory space for string buffers interrupting Neopixel LEDS on servo7/servo8 on omnibusf4pro and they stop working, so there's still more than 35Kbs of free space available and i cannot allocate more string buffers as it causing problems for Neopixel LEDs