Experiences with Mega328PB? - Page 1
Forum section: electronics / general

author: Wojta
author_rank: Contributor
timestamp: June 18, 2017, 04:01:04 pm
content: Hey all,Im building a weather station so I was recently looking at AVR chips that could be used. As a bit of arduino guy my eye obviously landed on the mega328P, Im pretty used to it so I was pretty stuck to getting that one.However then I realized Atmel (Microchip to be exact) made a new version, the Mega 328PB. I thought it could be pretty nice to get my hands on a "new technology", some of the features are awsome to have but I have no idea how different is it from the standard 328P (not featurewise but programingwise, in C). Does anyone have a experience with that chip? Is it even worth it getting it? Im a bit scared it could introduce some bugs but as I read only rev. A had something wrong I think. Also I have these chips available in two types, ATMEGA328PB-AN and ATMEGA328PB-AU, I wasnt able to spot a difference, do you know of any?Thanks,have a great day!

author: fmaimon
author_rank: Unknown
timestamp: June 18, 2017, 04:09:43 pm
content: All the differences are highlighted in this AN:http://www.atmel.com/Images/Atmel-42559-Differences-between-ATmega328P-and-ATmega328PB_ApplicationNote_AT15007.pdfIf you are interested only in code execution only, this note from the AN summarizes it well: "Code compiled for ATmega328 variants are compatible and can be executed in the ATmega328PB device. Whereas, reverse code compatibility is not guaranteed."Regarding the AU vs AN difference, it is explained in the datasheet in the "Ordering Information" page.

author: Wojta
author_rank: Contributor
timestamp: June 18, 2017, 04:17:38 pm
content: Yeah, thanks, just me being blind. Still I dont get the table with the different types. Is it that one of them is pb-free and the other one is not? Its obvious I guess but I just dont see it...Whoops, see it. The temperatures, right?

author: FreddyVictor
author_rank: Regular Contributor
timestamp: June 18, 2017, 04:40:46 pm
content: Quote from: Wojta on June 18, 2017, 04:01:04 pmit's actually pretty obvious when you look at them:http://uk.farnell.com/w/c/semiconductors-ics/microcontrollers-mcu/8-bit-microcontrollers-mcu/prl/results?st=atmega328pb

author: Wojta
author_rank: Contributor
timestamp: June 18, 2017, 04:57:01 pm
content: Quote from: FreddyVictor on June 18, 2017, 04:40:46 pmNot that obvious, the chips shown on that page are AU and MU, Im looking for a difference between AN and AU. Maybe Im just not getting the markings, If so, sorry...

author: Bruce Abbott
author_rank: Frequent Contributor
timestamp: June 18, 2017, 06:42:21 pm
content: Quote

author: igendel
author_rank: Frequent Contributor
timestamp: June 18, 2017, 06:46:34 pm
content: Quote from: Bruce Abbott on June 18, 2017, 06:42:21 pmYes, I almost lost a project/client because I was unaware of this "feature"...

author: Wojta
author_rank: Contributor
timestamp: June 18, 2017, 06:55:14 pm
content: Thanks for pointing that out. Im pretty sure that would stop me for a while

author: Wojta
author_rank: Contributor
timestamp: June 18, 2017, 07:33:13 pm
content: I read a bit about the oscillator options and low power is the "closest" to the full swing right? Maybe Im saying it wrong. I mean the same crystal circuit still applies , but the max frequency it can run on that is 16Mhz, not 20. Am I correct or mistaken again?Thanks for your patience with me guys

author: igendel
author_rank: Frequent Contributor
timestamp: June 18, 2017, 07:44:26 pm
content: Quote from: Wojta on June 18, 2017, 07:33:13 pmMy design (with a regular 16-MHz HC49 crystal) failed, that's how I learned about this issue in the first place. But maybe crystals with different/high quality specs will work.

author: L1L1
author_rank: Regular Contributor
timestamp: June 19, 2017, 04:39:15 pm
content: As part of anIoT project, I paired a 16Mhz crystal with an Atmega328PB and it works just fine.FYI, it's an Abracon ABM3-16.000MHZ-B2-T.It's true that the signal on the atmega's clock pins is rather weak but it seems to be enough nevertheless.Here's a write-up with more details:http://omzlo.com/articles/using-an-external-crystal-on-the-atmega328pb

author: Wojta
author_rank: Contributor
timestamp: June 20, 2017, 03:46:16 pm
content: Lovely, thank you.

author: colorado.rob
author_rank: Frequent Contributor
timestamp: June 20, 2017, 05:57:02 pm
content: I've been using the inexpensive Epson TSX-3225 16MHz 9pF crystals with my 328PB parts with good success. They're about 30% less than the Abracon part.

author: L1L1
author_rank: Regular Contributor
timestamp: June 23, 2017, 06:51:15 am
content: Quote from: colorado.rob on June 20, 2017, 05:57:02 pmI tried those as well with a 328PB. While I had no trouble soldering them with hot air, I got a lot of failures once I moved to a reflow oven. Not sure why.The Abracon part is easier to handle. In fact you can even solder it with a regular iron.

author: colorado.rob
author_rank: Frequent Contributor
timestamp: June 25, 2017, 03:05:24 am
content: Quote from: L1L1 on June 23, 2017, 06:51:15 amThat's really odd. I have a reflow over and hot-air rework station. Almost all boards done these days with reflow (cheap T962) by me and by my board manufacturer. I can't say I have ever seen a crystal failure.What you say really doesn't make sense to me since reflow is easier on the crystal than hot air since you have a well-regulated temp profile.