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Topic: Atmega328 vs Atmega328p....what are the differences? (Read 15 times) previous topic - next topic


title says it all, what are the differences?  i am thinking there would be an issue burning a bootloader to the 328 since it is probably expecting the 328p, and is the 328 newer or older than the 328p?  everything i have has a 328p in it but the 328 is $1 cheaper and that adds up quick in volume, so please let me know the difference.


Coding Badly

Looks like the P uses a bit less power and has a few more machine instructions.


The 2 devices have a different signature. I added the 328 to my Arduino and AVRDude files so that makes it easier to burn a bootloader. Once the bootloader is loaded they are interchangeable in the Uno board so the Uno config is sufficient to program them. I have a couple 328's that I have installed the bootloader on. they have all been in my arduino board and also in a wireless breadboard that has a MAX232 for a serial interface. Once the bootloader is loaded they all function the same with the ArduinoIDE.

Functionally I think the only real difference is in low power operation.


In addition to the power usage difference and the signature byte difference:

There's a Brownout difference:

BOD disable only available in picoPower devices ATmega48PA/88PA/168PA/328P
BODS and BODSE only available for picoPower devices ATmega48PA/88PA/168PA/328P

There's a couple of instruction differences, see page 522:

Mnemonics       Operands      Description                   Operation      Flags      #Clocks
JMP(1)              k                   Direct Jump                  PC <-- k          None      3
CALL(1)             k                   Direct Subroutine Call   PC <-- k         None      4

Note: 1. These instructions are only available in ATmega168PA and ATmega328P.
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
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