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DeveloperPermalink Reply by Andreas M. Antonopoulos on July 6, 2012 at 4:08pm

The dataflash erase issue is a known issue affecting a few % of boards. This issue is addressed has already been patched and tested and is awaiting upcoming release. 

I've had intermittent verification and flashing problems, the timing is a bit finicky, especially if you're going through a VM on a Mac (I've seen similar behavior occasionally). Mission Planner flashing on a PC is 99% reliable, on a VM about 75%. I just workaround by repeating the process if necessary.

You're seeing similar issues I suspect with the MAVLink errors, however MAVLink is designed for "lossy" conditions so it doesn't matter in practice too much. 

I would recommend looking at qgroundcontrol, a native Mac GCS. It is not as tightly integrated w APM as Mission Planner, but works very nicely on Mac and has some great features. I find it easier for actual missions than running a VM. 

I believe your board is fine. By next release the dataflash issue will be gone...

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DeveloperPermalink Reply by Andreas M. Antonopoulos on July 6, 2012 at 4:13pm

I don't know if you like CLI, but if you do then you *must* check out Tridge's amazing python ground control station MAVPRoxy. 

It is a modular, python based CLI interface, GCS, MAVLink proxy, MAVLink repeater and RC simulator. 

Tridge recently added several new developments and a module system, including a GUI using wxPython and a recently added lightweight web browser moving map which can be loaded in a smartphone screen too. 

It's the ultimate hacker's GCS

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Permalink Reply by Stephan Hiltenkamp on July 7, 2012 at 2:28am

Thanks for answering so quickly!

It is only partly comforting to know that I have an "affected" board.. :-) However, I am going on a business trip tomorrow so maybe the new version is released by the time I get back next weekend? Is there an ETA for the new version (what is that going to be? 2.6.1?).

If not -  I was counting on using this project to get back into programming. I might want to get kickstarted by necessity of rolling my own firmware. Is there a Mac specific beginners guide for Arduino programming, you can recommend?

In the meantime is there any test I can do to confirm that that is the only issue with my board / firmware combination?

Browsing through the source repository I have seen the notes about the flash issues, so I was half expecting this answer (why do I always have to be so lucky?).

I also think that the communication issue is only affecting the uplink (seen from the board) direction. I find it hard to believe that a corrupted downlink during firmware writing would result in anything bootable although during flashing there might be a different serial communication stack at work than in normal operation.

APM seems to use a non-stock library for  serial communication. I find it quite questionable to see the many communication errors, when other devices work fine. 115.200 bps is not really challenging in any way even for a USB to VM handover, so I am wondering whether we can't get better with the MAV link. It may be fault-tolerant but seeing up to 75% corruption on a 4 ft. cable isn't reassuring. Looking at the communication path it is the 32U2 handling the USB <-> serial conversion, then a regular serial link to the main processor on its pins PA1 and PA2?

I can't seem to find the code for the 32U2 serial stack - maybe you can point me to it? I am curious how many buffers there are on the way between PC and 2560.

I will try the other GCSs but for starters I was very pleased with the userfriendliness of Mission Planner. CLI is fine, I am an old (since 1994) Linux adept... but as life progresses time for hobbies gets less.

Thanks for your help, Otto

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