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On my Arduino UNO the chip part number is ATMEGA328P-U, i recently bought a ATMEGA328-PU to make a standalone Arduino. realized the part number differences after receiving the package...

I noticed that some arduino UNOs have the chip with part number of ATMEGA328P-PU! I'm totally confused!

Those chip are the same? can i use the one that i bought for an standalone Arduino?

If no what are the differences?

8

The main difference is the bit before the -. That is, the 328 vs the 328P. The "P" there denotes "Picopower" which allows the chip to run at very low power consumptions.

Basically the P version is a more modern version of the non-P chip. There are probably other internal differences too but you will have to check the datasheets thoroughly for those.

Everything after the - is to do with the packaging and environmental grading of the chip. For example PU is a -40C to +85C grade DIP chip. ANR is a -40C to +105C grade TQFP chip, etc.

If you see 328P-U then that's probably a fake chip. There's no such thing as single U suffix.

3

There are three die types:

328

328P

328PB

all have different signature bytes which may or may not impact loading code into them. Generally tho the programming software needs to know which part type is being used, at a minimum for installing bootloader code. Serial downloading may end up ignoring the signature bytes of a bootloaded part.

They can be had in different packaging, this is what Digikey is showing as available options:

-PU - 28 pin DIP

-AU - 32 pin TQFP

-AN - 32 pin TQFP

-MM - 28 pin leadless package, smaller than 32 pin leadless

-MN - 32 pin leadless package

-MU - 32 pin leadless package

-15AZ - 32 pin TQFP, rated for a higher temperature range

-15MZ - 32 pin leadless package rated for a higher temperature range

Any letters to the right of those seen when ordering indicate the method they are supplied - loose parts, parts in a reel, parts in a tube, etc.

Anything else is either an older part that did not follow the convention, or is a counterfeit part.

Tables 38.7 and 38.8 lists these options for the 328 and 328P for example, with H indicating a type of lead finish, and R indicating Tape & Reel availability:

http://ww1.microchip.com/downloads/en/DeviceDoc/ATmega48A-PA-88A-PA-168A-PA-328-P-DS-DS40002061A.pdf

ATmega328-AU

ATmega328-AUR

ATmega328-MMH

ATmega328-MMHR

ATmega328-MU

ATmega328-MUR

ATmega328-PU

And 328P options:

ATmega328-AU

ATmega328-AUR

ATmega328-MMH

ATmega328-MMHR

ATmega328-MU

ATmega328-MUR

ATmega328-PU

With these rated to 105C

ATmega328P-AN

ATmega328P-ANR

ATmega328P-MN

ATmega328P-MNR

ATmega328P-PN

I think you need to pull up the Automotive data sheet to see the Z numbered parts.

And the PB is a different data sheet as well.

  • That help a lot, but in case other people are finding this looking for ATmegaXX-XXPI, then: PI are 40-pin, PDIP – rasmusm Nov 24 at 19:19
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    '328s are never 40-pin. There are 40-pin DIPs in the Atmega family, and some, like the '644, '1284P, have been brought into the Arduino IDE. I like the '1284P myself; 32 IO arranged as 4 8-bit ports, dual hardware serial, 128K flash, 16K SRAM (twice what the '2560 has). – CrossRoads yesterday
  • Good point and my comment was more general for ATmega's, as this is the first google hit and your answer are a good reference, so i just wanted to add the answer to my own question there was about ATmega16-16pi, just in case it could help somebody else finding this looking for that. – rasmusm yesterday

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