How to access Tempe on FR920XT

Former Member over 9 years ago

Hello,

i would like to know how i can access the Tempe by Monkey C on a Freerunner 920XT.

So specific i would like to know how this datafield does it: https://apps.garmin.com/de-DE/apps/c745113e-64a5-423e-bfe6-e2124089fa31
I played a bit around and got the idea that they implement the hole Ant+ connection procedure in it. So i searched for a documentation about the protocoll. But i didnt find anything so i am asking your help. If anybody knows something i would be glad to get some more informations.

Best regards Leachim.

Top Replies

travis.vitek over 9 years ago +1

But it is very hard without a debuging system, is there any way to debug this?

If you have an ANT+ USB Stick, you can connect to the sensor from the simulator, which makes it a lot easier to iterate.
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All Replies

DaveBrillhart over 2 years ago in reply to travis.vitek

I'm running into the same issue. Your reply seemed to address Min Temp. I put the TEMPE in the freezer to test. The TEMPE reacts faster than my EDGE 1030 ("Device"). It appears once the TEMPE dropped below 32F (0C), my MSB/LSB logic failed. Any ideas? Is this a signed/unsigned thing?

DaveBrillhart over 2 years ago in reply to travis.vitek

This seems to work for me for the 16-bit signed current temp. once I've added payload 7 to payload 6 to get the value... the value is good as-is unless either of these two conditions exist. Then just divide by 100.

if (value == 0x8000 || value > 0xffff) { value = null; } // invalid for 16-bit signed
else if (value >= 0x8001) { value = value - 0x10000; } // substract 65536

DaveBrillhart over 2 years ago in reply to DaveBrillhart

I figured it out...

if (value == 0x8000 || value > 0xffff) { value = null; } // invalid for 16-bit signed
else if (value >= 0x8001) { value = value - 0x10000; } // substract 65536