Fez Cobra II - RTC: Battery or supercap

Hello everyone, just getting to grips with my new Fez Cobra II and I was wondering what the opinion was on using Supercaps for the RTC? I dont know anything about them but it sounds like a good alternative to a 3.3v battery.

First I just want to check, I just need to wire a battery up with positive to the RTC pin and then the battery ground to the ground pin on the board?

If I wanted to use a super cap would I need anything else? How would I wire it up?

I assume I dont need a crystal either and its all built in?



hmm good point. I am considering creating a Car stereo system with MP3 and Radio playback, I thought a super cap would be a good idea as I wouldnt have to remove it all from the dash in order to replace the battery. Of course I have the option of using the constant power from the car battery but I would be afraid doing something wrong and draining the battery by accident while I am miles away from home :oP

I guess the board could be powered off for up to two weeks when I go on holiday, not sure how long it would last on the supercap so maybe it wouldnt be a good idea. At the same time though its got a touchscreen so I will have a menu to setup the clock anyway if I need to reset it


@ Bodwad - FezConnect shield has supercap for RTC. You can check it in the schematics here:


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ooo good point about the temperatures I never thought of that. i am thinking I will keep it simple and just place a 3.3 volt battery on it, maybe in the future I will look at taking the power directly off the cars PSU but I wont risk it until I am more experianced lol

Thanks for your help, anyone with any other suggestions are always welcome though :o)


Why not a battery pack that you hang under the dash or in the glove box?

Yeah I have decided to start with a battery and see how it goes. In theory the battery should last a long time. Got it all working ;oD

Now I just have to sort out the stuttering audio :o(

Thanks for all the help everyone :o)