Pixhawk will not boot, Mavlink connection fails

Archive
1

This document has been created to capture the outcomes of a day’s work attempting to fault find a new and non-booting PixHawk module, in the hope to save someone some trouble.

On arrival, the bare Pixhawk was connected to a fresh install of Mission Planner V1.2.97, and the latest QUAD firmware installed by default actions. The hardware was subsequently installed on a frame with all it peripherals, and an attempt made to run the “wizard”. It was found impossible to complete and finding no “cancel” capability it was crashed out. This appeared to corrupt the PixHawk. as the module subsequently never completed a boot and would not enable MAVLINK communications.

Investigations reveled the possible solution, as described by Dave C. was to uninstall MP, cleanup all related HDD files (delete MP install folder) and cleanup registry entries. We used CC-Cleaner for the registry. This was followed by reformatting the Mini-SD card, remembering it is FAT32. It was found that just deleting the APM folder in the root was probably sufficient. MP was then reinstalled, and during power on the “FMU” reset button was held down.

This proved to be ineffective, with multiple attempts completed trying to figure out the required sequence. After 4 hours, it was determined there was no way to get the PixHawk to boot correctly as installed. It was decided to go back to the very beginning and apply some strict problem finding techniques, remembering it had worked (naked) out of the box.

Reset to the beginning

  1. Reformat the SD card (Delete APM folder)
  2. Remove all connections the PixHawk
  3. Uninstall MP and clean laptop.
  4. Reboot PC to ensure memory cleaned.

Restart over

  1. Download latest MP installer (even if you think you have the latest, do it again)
  2. Reload MP, and DO NOT run the wizard.
  3. Power on the PixHawk via the USB cable, and verify correct LED’s
    . a. FMU - Green power on, Red flashes then turns off
    . b. IO - Green power with flashing Red and Blue
    . c. Center LED’s active
    [color=#FF0080]At last, we had a booting PixHawk[/color]
  4. Reload the required firmware
  5. Ensure MavLink connection
    [color=#FF0080]At last, we had a MavLink connection[/color]

Now the issue was to try and replicate the fault. We completed the fault diagnostics by completing the following steps
• Add hardware
• Power on PixHawk
• Make MavLink connection
• Break MavLink connection
• Power down PixHawk

for the listed hardware, in this order
• Arm switch PixHawk booted
• Buzzer PixHawk booted
• Power module (no battery connected) PixHawk booted
• 2.4 Receiver PixHawk booted
• GPS only of the combined unit PixHawk booted
• Magnatometer Failed to boot
• Removed magnatometer PixHawk booted

The magnatometer was temporally replaced with a standalone item from a working APM 2.5 system and the PixHawk boot confirmed. All configurations and preflight tests were completed without any more issues.

The process is now at a standstill as a replacement GPS/Magnatometer unit is requested from 3D-Robotics

Morel of the process :
Do not believe the supplied hardware is serviceable !!!
Electronics fail early, or work forever (almost)

2

Check to make sure you have the correct 6 wire connector plugged into the GPS unit. There are two connectors supplied in the box both of the same size, one has 5 wires one has 6 you must use the one that has 6 wires to properly connect the ublox to the pixhawk. This will fix your problem I think.

Mark Miner

3

Mark,

Thanks for that. Unfortunately, in this case, no cigar. We had already double checked that.

Problem has turned out to be the PixHawk boot loader failing when it finds a compass that has not been calibrated. So how do you get past this catch 22? Answer :- Disable the boot loader error detection (totally), calibrate the compass, then enable boot loader again. Thereby bypassing the catch 22 completely.

Thanks to many and varied threads on the forums … it took 12 hours to track it all down.

From all this research, assuming we are reading it correctly, Where do you find the boot loader drop down list for selecting what it detects as an error, and what it will ignore?

A second and off topic question that has come up, does the GPS hardware indicate a 3D lock by a steady or flashing blue LED. We have a flashing LED, while the MP indicates it has a 3D fix. Everything we find says it must be solid, but we can’t seem to get that state.

4

Hey I’m running into this issue as we speak. I’ve looked for how to disable the boot loader error detection but i can’t find it. Is it an APM code tweak or is there something special you have to do?

Thanks in advance,

Toilet-Bowling-Mo-Fo

[quote=“SGMA pilot”]Mark,

Thanks for that. Unfortunately, in this case, no cigar. We had already double checked that.

Problem has turned out to be the PixHawk boot loader failing when it finds a compass that has not been calibrated. So how do you get past this catch 22? Answer :- Disable the boot loader error detection (totally), calibrate the compass, then enable boot loader again. Thereby bypassing the catch 22 completely.

Thanks to many and varied threads on the forums … it took 12 hours to track it all down.

From all this research, assuming we are reading it correctly, Where do you find the boot loader drop down list for selecting what it detects as an error, and what it will ignore?

A second and off topic question that has come up, does the GPS hardware indicate a 3D lock by a steady or flashing blue LED. We have a flashing LED, while the MP indicates it has a 3D fix. Everything we find says it must be solid, but we can’t seem to get that state.[/quote]

5

@wifiguru10,
If your GPS is a uBlox, then you should have a flashing blue led when there is a GPS lock.
If it is a MediaTek GPS, then it will flash blue until it gets a lock and becomes solid blue.
Regards,
TCIII GM

6

My GPS is working fine, it’s the onboard external compass (LEA6 based GPS with onboard compass) that i can’t get working. When i power the unit with the external compass configured it’ gives me the startup failed sound. If I disconnect it works fine.

I’m just trying to figure out how to do the following…
“Disable the boot loader error detection (totally), calibrate the compass, then enable boot loader again.”

[quote=“TCIII”]@wifiguru10,
If your GPS is a uBlox, then you should have a flashing blue led when there is a GPS lock.
If it is a MediaTek GPS, then it will flash blue until it gets a lock and becomes solid blue.
Regards,
TCIII GM[/quote]

7

I am suffering the same problem. Soon as I connect the external compass to the I2C plug the system will fail to boot. It boots fine with the GPS connected.

8

So swapped my compass out and it works fine. Had a brand new LEA6 GPS (fast acquire, very accurate) and a NEO6 (slower, cheaper). The lea6 worked fine with GPS but hung the boot when i plugged in the compass. With the older neo6, i have both plugged in and flying great without issue. So i guess there’s no magical process to get it working. Just check your hardware.

I’m guessing the pixhawk just doesn’t like some chips, or it pulls too much power and browns out. I had it working once or twice but never back to back. Might use the LEA6 just as a secondary GPS.

[quote=“wifiguru10”]My GPS is working fine, it’s the onboard external compass (LEA6 based GPS with onboard compass) that i can’t get working. When i power the unit with the external compass configured it’ gives me the startup failed sound. If I disconnect it works fine.

I’m just trying to figure out how to do the following…
“Disable the boot loader error detection (totally), calibrate the compass, then enable boot loader again.”

[quote=“TCIII”]@wifiguru10,
If your GPS is a uBlox, then you should have a flashing blue led when there is a GPS lock.
If it is a MediaTek GPS, then it will flash blue until it gets a lock and becomes solid blue.
Regards,
TCIII GM[/quote][/quote]