Using/Programing Atmega328p-AU with 3.3 Volts

Hello everyone,

In my PCB project, i have to use only one coin cell battery which they are usually around 3 Volts. Therefore, i decided to use the atmega328p with 3.3 volts by stepping up the 3 volts to 3.3 via voltage regulator.

However, Im not sure if i use 8 Mhz crystal/22pF capacitors and 3.3 volts, will they be enough to make the atmega328p work properly ?

In addition, I have to bootload it but i found some discussions about problems while bootloading the atmega328p 3.3 Volts. Just to solve this problem, is it possible to bootload and upload the codes to atmega 328p by using 16 MHz and 5 volt on a different board. I mean, after uploading the codes to atmega328p, i will remove it from the board which includes 16 Mhz crystal and works under 5 volt and put it to my main PCB which includes 8 MHz crystal and works under 8 MHz? (Im planning to use arduino uno to bootload.)

Lastly, what should be the connections of the pins like AREF, AVCC ? I saw many different schematics. While someone is directly connecting them to VCC, the others adds 0.1 uF capacitor between them and ground. I will use the ADC, then which connections do you advise ?

Thank you so much,

berkayozbek:
However, Im not sure if i use 8 Mhz crystal/22pF capacitors and 3.3 volts, will they be enough to make the atmega328p work properly ?

ATmega328P will work fine at 3.3 V and 8 MHz. You can always consult the datasheet for this sort of information.

berkayozbek:
i found some discussions about problems while bootloading the atmega328p 3.3 Volts.

I've never heard of that. Do you have a link to the discussion?

berkayozbek:
In my PCB project, i have to use only one coin cell battery which they are usually around 3 Volts. Therefore, i decided to use the atmega328p with 3.3 volts by stepping up the 3 volts to 3.3 via voltage regulator.

You can't step up voltage with a voltage regulator. You can only step it down (and you need a margin, called the "dropout voltage"). For stepping up voltage, you need a Boost (or step up) DC/DC converter, which takes up space and may produce EMI (electromagnetic interferences). The ATmega328P should work at 3 V, but you should check the other components to see if they would also work at 3 V.

arduin01:
You can't step up voltage with a voltage regulator. You can only step it down (and you need a margin, called the "dropout voltage"). For stepping up voltage, you need a Boost (or step up) DC/DC converter, which takes up space and may produce EMI (electromagnetic interferences). The ATmega328P should work at 3 V, but you should check the other components to see if they would also work at 3 V.

Boost converters are also known as step-up regulators. Here is an example.

I had never seen them called that way. Anyways, the odds the OP meant that are pretty low. It's more likely that he's a newbie that thinks that voltage regulators like the 7805 can step up voltage. I once thought, incorrectly, that op amps could step up voltage!