ATMEGA part number suffixes

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I have a stash of ATMEGAs that someone gave me, but I let the smoke out of some of them and need to buy more. I found out it's simpler when people give them to you. There are different part numbers, and different prices, but I can't find out the differences. Can someone point me to the AVR documentation that explains the part number suffixes?

This is from Digikey.

ATMEGA328-PU 3.93
ATMEGA328P-PU 4.98

I can't see any spec differences between these chips. Same with the 168:

ATMEGA168V-10PU 4.43
ATMEGA168PV-10PU 4.85
ATMEGA168P-20PU 4.85
ATMEGA168-20PU 4.43

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Quote:

I can't see any spec differences between these chips.

??? the P- and PV- ???

What is your spec question? The datasheets for the various models, if still shipping, should be available. Also, have you looked for migration app notes?

"AVR512: Migration from ATmega48/88/168 to ATmega48P/88P/168P "

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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I see the part number difference obviously.

When I check the datasheets, I don't see any differences. No, I didn't read all 35,000 words of both datasheets to compare them.

Is it safe to say I should just buy the cheapest one? It sounds like the differences are minimal.

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You tend to see the differences listed at the end of the spec sheet. Often, those numbers indicate rated clock speed. Sometimes, there are suffix letters that specify the package (DIP, TQFP, etc), sometimes low power options.

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

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As Jim says every AVR datasheet has an "Ordering Information" towards the back. If I pick the datasheet for mega48/88/168/328PA datasheet. The Ordering Info tells me that there are, for example, four variants of mega48PA:

ATmega48PA-AU 32pin TQFP
ATmega48PA-MMH(4) 28pad QFN
ATmega48PA-MU 32pad QFN
ATmega48PA-PU 28pin DIP

(all "industrial" with a -40..+85C temp range).

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Quote:

When I check the datasheets, I don't see any differences. No, I didn't read all 35,000 words of both datasheets to compare them.


Did you read the app note? What did it say? Perhaps that there are added I/O bits (read: features) in the P-chips?

Instead of the 35000 words, how about the first page9s) with the feature summary? Any differences? What about the next page, the pinout diagram? any extra alternate functions?

There used to be a link on the AVR8 page on the Atmel Web site about PicoPower devices.

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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-10PU - 10MHZ clock speed max
-20PU - 20MHZ clock speed max

The letters mean other things

Page1 of the mega 48/88/168 in the SPEED GRADE, and OPERTATING VOLTAGE: sections explains some of the letter meanings

Page 352 Table 33.3 explains ALL of the letter/number combinations.

Oh, I did not have to read 35.000 pages to find them either ;)

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I also found this hard to get to grips with, eventually finding that the current draw for various setings- idle/power down/sleep etc. were slightly lower for the P version.
I never did find out what the V was, and don't much care..Life is too short :(

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Quote:

I never did find out what the V was,

V has been around a long time for AVR models. V chips were/are qualified to run at the low end of the supply voltage range for a model, but generally are not qualified at the max speed for the model.

I said "were" as V is becoming passe as the A versions are rolled out--they are qualified over the entire supply voltage and speed ranges.

And I said "generally" 'cause I mainly deal with Mega48 family, Mega164 family, and a few TQFP64 and TQFP100 models. There may be families that don't necessarily follow the above but I think the summary about V generally applies; P PicoPower may be V or not; and A obviates V.

In fairness to OP, would it have been >>that<< hard for Atmel to list the I/O register changes in the migration app note?!?

Quote:

Is it safe to say I should just buy the cheapest one? It sounds like the differences are minimal.

In practice, fogr general work, indeed choose whatever model you want. You might be more particular if you are going to run at max speed or min supply V. Or if you want power saving. Or you want longevity for your production design without re-qualifying when a flavour becomes unobtanium.

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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Quote:

In practice, fogr general work, indeed choose whatever model you want. You might be more particular if you are going to run at max speed or min supply V. Or if you want power saving. Or you want longevity for your production design without re-qualifying when a flavour becomes unobtanium.

Watch out for nasty "gotchas" such as how many UARTs a mega324 versus a mega324P have ;-)

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Quote:

Watch out for nasty "gotchas" such as how many UARTs a mega324 versus a mega324P have

OK, I'll bite. My guess is two for each.

(Did you mean "Mega644"?)

Anyway, to avoid comparing 35000 words, a few pages will help greatly:

-- First page or two with the Feature description
-- Following page or two with the pinout/alternate functions
-- Ordering Information (which leads to packages)
-- Register Summary
-- Revision History

The Feature description and Register Summary will help Cliff with his '324 inquiry.

A related question: How many 16-bit timers are on a Mega1284 in various letter flavours?

Lee

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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Rather than datasheets (assuming you can trust Atmel to create XML/.h files!) I prefer:

C:\Program Files\Atmel\AVR Studio 5.1\extensions\Atmel\AVRGCC\3.3.1\AVRToolchain\avr\include\avr>grep UDR. iom324* | gre
p SFR_MEM
iom324a.h:#define UDR0    _SFR_MEM8(0xC6)
iom324a.h:#define UDR1    _SFR_MEM8(0xCE)
iom324p.h:#define UDR0    _SFR_MEM8(0xC6)
iom324p.h:#define UDR1    _SFR_MEM8(0xCE)
iom324pa.h:#define UDR0 _SFR_MEM8(0xC6)
iom324pa.h:#define UDR1 _SFR_MEM8(0xCE)

C:\Program Files\Atmel\AVR Studio 5.1\extensions\Atmel\AVRGCC\3.3.1\AVRToolchain\avr\include\avr>grep UDR. iom644* | gre
p SFR_MEM
iom644a.h:#define UDR0    _SFR_MEM8(0xC6)
iom644a.h:#define UDR1    _SFR_MEM8(0xCE)
iom644pa.h:#define UDR0 _SFR_MEM8(0xC6)
iom644pa.h:#define UDR1 _SFR_MEM8(0xCE)

C:\Program Files\Atmel\AVR Studio 5.1\extensions\Atmel\AVRGCC\3.3.1\AVRToolchain\avr\include\avr>grep UDR. iom164* | gre
p SFR_MEM
iom164a.h:#define UDR0    _SFR_MEM8(0xC6)
iom164a.h:#define UDR1    _SFR_MEM8(0xCE)
iom164p.h:#define UDR0    _SFR_MEM8(0xC6)
iom164p.h:#define UDR1    _SFR_MEM8(0xCE)
iom164pa.h:#define UDR0    _SFR_MEM8(0xC6)
iom164pa.h:#define UDR1    _SFR_MEM8(0xCE)

So it's none of 164/324/644. So what chip is it I'm thinking of that has 2 UARTs in the P version and only one in the non-P version?!?

Or is this because there really are 164/324/644 without even an A (and, apparently, .h files in 5.1)

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Quote:

So what chip is it I'm thinking of that has 2 UARTs in the P version and only one in the non-P version?!?

Mega644.
I have the G datasheet from 2006, "not recommended for new designs", one USART. (that was in the locked datasheet generation so I cannot print excerpts.

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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Quote:

Or is this because there really are 164/324/644 without even an A (and, apparently, .h files in 5.1)

Well, for that particular Infinite Value toolchain that uses iom*** created however.

What does ATmega644.xml in PartDescriptionFiles say? And the resulting .h from using XMLCONVERT?

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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Well interestingly it seems that in AVR-LibC for 5.1 there is a short iom644.h that gets the majority of it's definitions from iomxx4.h which then has:

#if !defined(__AVR_ATmega644__)
/*
 * Only ATmega164P/324P/644P have a second USART.
 */
/* Reserved [0xC7] */

#define UCSR1A	_SFR_MEM8(0xC8)

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That all makes sense, then.

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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I could have sworn I'd read here that the 324 was similarly afflicted. Guess this goes to prove you shouldn't believe everything you read on the internet!

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@theusch - FYI - you can often open locked pdf's by using a NON-adobe reader

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Quote:

@theusch - FYI - you can often open locked pdf's by using a NON-adobe reader


I was using FoxIt.

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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The cheapest chip on digikey is the ATMEGA328-PU, which looks pretty standard for hobby purposes. I do want to run at 16MHz, but I don't need very low voltage.

I still think they aren't very straightforward about describing the differences, if you have to bounce to a bunch of different sections of the datasheet to try to piece together the difference between a 328 and 328P.

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Quote:

piece together the difference between a 328 and 328P.

But those are not described in the same datasheet? They are different models and each have their own datasheets.

(the P (P="Picopower") has more power saving features including registers and control bits than the non-P)

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Quote:

The cheapest chip on digikey is the ATMEGA328-PU

That is very interesting, as in general the A chips are less expensive. But then again, qty. 1 prices can be all over the map.

Aaah, I see now--the PA variant is not yet listed for a '328. PA in TQFP is indeed less expensive than prior at Mouser. Further hmmm--Mouser lists ATMEGA328-PU as a "new part", $2.82 qty. 1, and with no speed grade number -nnPU it sounds like an A part.

Confused yet?

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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Yes.