Have the AP Mega and IMU assembled, have done some basic tests to switch led's on/off etc.

One thing I can not get working and have trouble debugging is the ADC, all the test program returns is a row of 0's.

Any ideas how to debug ?

The code I used is the files as below for the libraries and APM_ADC_test.


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Make sure you're only powering the board with USB or FTDI, not external power, during the test.

Try the attached code. Make sure that the APM_ADC folder is in the IDE libraries folder.

@Chris the board is powered from USB
@Thomas that is the code I am using, it is the same as the one listed in my post

Interesting. The code runs fine on my APM and returns the expected values. I assume that you are using the Arduino IDE monitor to view the data stream from the APM?

It works fine on all my boards, too.

Hein, check your soldering?
@Chris @Thomas

Using Arduino IDE (v 0018) to monitor the output. Back to basics, Chris's suggestion is the route, re-check all the soldering. Thx

The issue was with the main ArdupilotMega board, one of the connector pin holes was not connected to the rest of the trace to the 1280. Had to put a jumper wire across from the pin to the 1280 to correct it. Looks like the board had a defect as after de-soldering there is no metal on that hole :(
Does not look good but at least I have what looks like good values from the APM.
Thanks for reporting back. Can you post a pic of the bad trace, in case others have this problem?

(I haven't seen it on any other boards, but these things do happen).

Great detective work!
Put in a temporary jumper to fix so I can continue testing with the software. It obscures the defect. If I redo the jumper to be more reliable and neat I will take a clean picture.

@Hein: is it possible to have a better picture as I really think to have the same problem?


Hmm I am only getting zeros as well.  My board just arrived today.  I've tried both the "test" mode and the ADC test program directly.  Barometer and radio work fine.


Photos: https://picasaweb.google.com/john.t.erickson/ArduPilot




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