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TeleMega boots always in idle

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thomas

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I have some problems with my Telemega V1.0 firmware 1.64,
Regardless of the orientation Up, down or horizontal my Telemega boots always in the idle mode.
Also if I reboot it over the radio.
The next problem is, I can not communicate with it over usb, neither on Windows or on Linux.
I have tried to load the bootloader mode to recover from a bad firmware flash but even then I can not see the device. Maybe I can pair program it, I need to solder the 4pin mico match connector to the debug port for that, right?
I can configure it over the radio with Linux, Windows and Android.
I had a look at the acceleration values in idle mode and it seems they are all negative -5m/s^2 antenna up, -25 antenna down, -15 horizontal

I tired to send this on the altusmetrum mailing list but somhow my email gets rejected.
 

keithp

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I have some problems with my Telemega V1.0 firmware 1.64,
Regardless of the orientation Up, down or horizontal my Telemega boots always in the idle mode.
Also if I reboot it over the radio.
The next problem is, I can not communicate with it over usb, neither on Windows or on Linux.
I have tried to load the bootloader mode to recover from a bad firmware flash but even then I can not see the device. Maybe I can pair program it, I need to solder the 4pin mico match connector to the debug port for that, right?
I can configure it over the radio with Linux, Windows and Android.
I had a look at the acceleration values in idle mode and it seems they are all negative -5m/s^2 antenna up, -25 antenna down, -15 horizontal

I tired to send this on the altusmetrum mailing list but somhow my email gets rejected.
Sounds like the device needs re-calibration to get the accelerometers usable again. And, perhaps the USB connector has been damaged?

TeleMega doesn't use pair programming, so if you can't talk to it over USB, you can't reprogram it.

The altusmetrum mailing list only lets subscribers post to avoid huge volumes of spam. We have a 'contact us' link on our shop:

http://shop.gag.com/contacts/

Let us know if you'd like us to repair the board.
 

thomas

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Hi Keith thanks for the reply,
I have checked the USB port and electrical it is fine. I have replaced the USB cable and apparently it was broken. Pretty stupid that I have not checked this before.
So I can now connect the Telemega over USB.
I have flashed the newest firmware, but that did not magically repair it. :)
But I can now see the serial dump to the console.

Can I recalibrate the accelerometer myself?

I thought that I am a subscriber to the list because I receive the mails.
 

keithp

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Yeah, I've got numerous broken USB cables; I'm trying to remember to stick them in the trash when they fail.

Yes, you can recalibrate the accelerometer, but you need a terminal program like putty to do it. If you're comfortable using a command line, you can use AltosUI to figure out which COM port TeleMega is connected to, and then use Putty to talk to it. There's online help with the '?' command. Calibrating the accelerometer is done with the 'c a 0' command, which has prompts to lead you through the process. Then save the new values with 'c w' command.
 

thomas

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Great, now it is working again.
Thanks a lot.
 
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keithp

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Awesome! Glad you were able to figure this out; we should document the procedure.
 

thomas

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So I cut the USB cable and found out that there are only two wires inside. :facepalm:
Apparently it was only useful for charging stuff and some stupid engineer though he could safe some cents.
 

Random Flying Object

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Glad I found this thread. Wondering what your peak acceleration was on the flight prior to the calibration issue?
 

Salvage-1

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Hmmm and this might just be the route to fix my TeleMaybe
 

Random Flying Object

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Looks like the cal instructions for the "c a 0" command are inverted. This is on a couple of TeleMega V1 boards both with firmware 1.7.

I had an issue with one of my TM's after a purposeful abusive high G flight at BALLS last year. Was confused about pad orientation, hence accelerometer calibration seemed liked a good idea.

I performed the accel cal procedure on the TM and found that it failed every time with "Invalid accel: up (2056) down (2020)".

Using the command "c s", it displayed the current cal settings as 2030 & 2067. Notice the smaller number first. I manually entered and saved the 2056 and 2020 numbers from the failed cal, but in reverse order, everything worked.

So, I went back through the call process. Instead of orientating the antenna up when asked, I oriented it down and visa versa. Everything seems good now. I figured this was a bit strange so I performed the exact same procedure on a back TM V1 with rev 1.7, saved the proper calls to the proper place.

Can someone please verify this before folks start calibrating there TM V1 boards backwards?
 

keithp

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Can someone please verify this before folks start calibrating there TM V1 boards backwards?
I'd bet you've got the device configured to fly in 'Antenna Down' position instead of the default 'Antenna Up'. You should set your device to Antenna Up mode before trying to calibrate the accelerometers.
 

Random Flying Object

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I'd bet you've got the device configured to fly in 'Antenna Down' position instead of the default 'Antenna Up'. You should set your device to Antenna Up mode before trying to calibrate the accelerometers.
You bet correctly. I did have both configured for antenna down. I changed the flight/idle condition to antenna up and the calibration worked per the prompts during the "c a 0" command.

Any theories on the drift of the sensor? It has seen some fairly high temps and time averaged acceleration around 60g.
 

keithp

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Any theories on the drift of the sensor? It has seen some fairly high temps and time averaged acceleration around 60g.
The data sheet for the part doesn't include any information about long-term drift at all. Of course, it expects to live in a 1g field almost all of the time, and has internal offset adjustment that averages the data over a "long period" (on the order of seconds) and adjusts the reported value. Obviously, when operated in that mode, the device doesn't appear to drift. We can't use that mode, so we get some drift over time. I'll add 'recalibrate accelerometer' to the wish list of features for Altosui and see if I can't find time to add that in the next release.
 

Random Flying Object

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Tested the recalibrated TeleMega and three other EasyMini's on a flight to 10kft. Everything worked great and all data agreed. Thanks Keith.
 
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