Making Arduino Pro Mini development board plus AA battery question

Using Arduino General Electronics
#1

Hello

Just a bit of advice, I’m planning on making a little development board to plug a mini straight into, for ease of programming. A little like the Nano one which you can buy off ebay (see photo). Although, not as complex, as in not a reset button and possibly not extra power rails, we’ll see.

I’m planning on power it up with a plug in psu, so I’ll get a female jack (if thats the correct name?). Should any resistors be put into place or capacitors? For anything other than input voltage. Anything incase there’s a spike in voltage, for protection.

On a separate note, for testing I was going to use either 2 or 3 AA NiMh batteries and directly connect to the RAW pin. Should a use a voltage regulator to maintain over 3.3V or just let the brown out function do it’s thing. Or increase the BOD fuses so it cuts out at say, 2.8V.

I looked for a tutorial but couldnt find anything.

Thanks

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#2

When you run from batter (2AA), use a 8MHz quarz (or non at all) and run 1Mz, then you can set brounout to as low as you like.

#3

Lets say I didnt change the brown out configuration, would it be okay not changing the speed which it’s running at? Need to check the spec of the batteries which I have

#4

Please look at the atmegas datasheet. at 3.3V you 16MHz is not guaranteed, <3V it won’t work.

#5

Ah is that the reason. Okay, will do. Was just reading about reducing the Mhz. If it’s for a RF circuit, should both units speeds be reduced, or does that not matter?

#6