Differences between ATMEGA328P and ATMEGA328P-AU and ATMEGA328P-PU

Hello guys
I want to know what differences are there between ATMEGA328P and ATMEGA328P-AU and ATMEGA328P-PU.
And another question,I have some new chips ATMEGA328P-AU,
How can I boot-load them with uno r3?

There is no such thing as an "ATmega328P" with no additional suffix.

The -PU and -AU suffixes indicate packaging and temperature range -P indicates a DIP, -A indicates a TQFP, and -M is a QFN. U means "industrial" temperature range. (This is all described in the "Ordering Information" section of the Atmel Datasheet, which is usually followed by the "packaging information" section that describes the details of each package.

Saying "atmega328p" without a suffix would refer to "any" packaging option. As in "The Arduino core libraries run on the ATmega328p processor"; the libraries don't care what the package is, only about the operation of the chip itself (all of the packages contain the same silicon chip. They're just connected to pins arranged in different shapes.)

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So,what is differences between "Atmega328p","Atmega328"?
Here what does 'p' refer to?


"p" before the dash means "picopower"; the 328p and 328 are NEARLY identical (I think the p allows the brownout circuitry to be disabled to same a bit of power, and that's about the only difference anyone has found. (Hypothesis: a 328 is a 328p die that didn't meet power consumption specifications during wafer-level testing.))

There is now also a 328pb, which apparently is substantially different: it has two UARTs and two TWI interfaces, for instance, and a couple of extra timers. And it's not available in DIP.

Personally, I don't understand Atmel's part numbering. (for instance, the ATmega168pb is much closer to the 168p than the 328pb is to the 328p. Sigh.)