Getting serial to 2.8v

Hi,I have Atmega328p and I need serial to be 2.8v because it will be connected to SIM900.It will be powered from 5v so I was thinking voltage devider for this,I calculated 10000R and 12000R to give me output of 2.727V,will that work? or will it mess with my serial? or do I need higher values? 100k and 120k?

You need something like this: or similar.

Yes,but I can't get it right now,will the voltage devider work?

What baud rates? High value resistors will limit the bandwidth.

9600 baud

Maybe, but I've had issues with reliability when I've tried to do it with a divider. In the end, you really want that level shifter if you want things to be solid.

You can make your own level shifter if you have a couple of transistors. You don't have to buy one ready made.

I have mosfets,N-channel ones


These Level Converter work for 5V to 3.3 volts. Will probably work down to 2.8

The schematic for it (or at lease one very similar) is attached. You can use your Mosfets IF their Vgs is low enough to allow the Mosfet to be On with the 2.8 V you will supply from one end.

Good luck

Thanks for helping.I have 500 of this ones: what should I be looking in datasheet to check what's minimum voltage for it?

I got it to work,thanks