16MHz vs 8MHz internal and IRLib

Projects General Guidance
1

Hi, not sure if this is the right forum but here goes.

I have built a PWM controller for some LEDs that are controlled via an IR remote. It all works absolutely dandy on an Uno at 16Mhz but if I compile and upload to a stand alone 328P using the internal oscillator then the receiver is unresponsive. I know the program is running fine as the LED's behave properly. I am using an internal oscillator on breadboard board definition. I highly suspect that the IRLib timings are way off and I will have to run my final design at 16MHz but I want to understand a few things.

When compiling, do libraries assume that the AVR is a 16MHz?
If not, is this something that is set in board definitions and the one I have could be innacurate? (I downloaded the board def and I cannot remember where from)
Is 8MHz just simply to slow for decoding the signal?

Thank you!

2

In the Arduino IDE, you MUST select the appropriate "board" option under the "Tools" menu, which informs the compiler of the CPU clock speed.

3

I have a board definition for a 328P on breadboard with internal clock, but as I say I have no idea where I got it from. I will see if I can find a better one as it seems there is not a built in definition for what I am after.

4

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5

Brilliant, it didn't work with that definition but it did get me poking around at the board definitions and noticed my fuses were set differently to the definitions. I am now up and running, thanks so much for your help :slight_smile:

6

Thanks, this is just what i needed. I had changed the board type but it was assuming it was 5V 16Mhz mini, I have 3.3V 8Mhz minis. After changing the processor type irlib2 worked great on the mini pro.