ATmega328PB board at Pololu

Go To Last Post
15 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

https://www.pololu.com/category/239/a-star-328pb-micro

 

There are 16MHz and 20MHz options, each with 5V and 3V3 options.

 

 

EDIT

 

Sorry, that's wrong: the options at 3V3 are 8MHz and 12MHz

 

blush

Top Tips:

  1. How to properly post source code - see: https://www.avrfreaks.net/comment... - also how to properly include images/pictures
  2. "Garbage" characters on a serial terminal are (almost?) invariably due to wrong baud rate - see: https://learn.sparkfun.com/tutorials/serial-communication
  3. Wrong baud rate is usually due to not running at the speed you thought; check by blinking a LED to see if you get the speed you expected
  4. Difference between a crystal, and a crystal oscillatorhttps://www.avrfreaks.net/comment...
  5. When your question is resolved, mark the solution: https://www.avrfreaks.net/comment...
  6. Beginner's "Getting Started" tips: https://www.avrfreaks.net/comment...
Last Edited: Wed. Feb 21, 2018 - 11:48 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

For the 20 MHz version they write :

Speed warning for 20 MHz version: The 20 MHz resonator frequency exceeds the maximum explicitly allowed in the ATmega328PB datasheet. In our basic testing, the 20 MHz resonator appears to function without problems, but for any critical applications you should confirm for yourself that this product is appropriate.

So it seem's that the chips are getting better ! (the first version would not run). 

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

"There are 16MHz and 20MHz options, each with 5V and 3V3 options."

 

for 3V3 both options are out of the spec.

 

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Actually, that was my mistake - I've updated my post.

 

blush

Top Tips:

  1. How to properly post source code - see: https://www.avrfreaks.net/comment... - also how to properly include images/pictures
  2. "Garbage" characters on a serial terminal are (almost?) invariably due to wrong baud rate - see: https://learn.sparkfun.com/tutorials/serial-communication
  3. Wrong baud rate is usually due to not running at the speed you thought; check by blinking a LED to see if you get the speed you expected
  4. Difference between a crystal, and a crystal oscillatorhttps://www.avrfreaks.net/comment...
  5. When your question is resolved, mark the solution: https://www.avrfreaks.net/comment...
  6. Beginner's "Getting Started" tips: https://www.avrfreaks.net/comment...
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I was just looking over the datasheet and while there is a specification for EXTCLK (20MHz), there is nothing in the electrical characteristics about the XTAL oscillator.  The only indication of maximum XTAL oscillator frequency is in the CLKSEL range setting, which indicates  the maximum range of 8.0 - 16.0 MHz.  So, per the datasheet, the only way to clock the 328PB @20 MHz is via an external clock source.  Seems a bit odd, doesn't it?

 

From the datasheet bookmarks.  No mention of the XTAL oscillator:

 

External clock spec:

 

 

 

EDIT: added while

Greg Muth

Portland, OR, US

Xplained/Pro/Mini Boards mostly

 

Make Xmega Great Again!

 

Last Edited: Wed. Feb 21, 2018 - 05:14 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Greg_Muth wrote:

I was just looking over the datasheet and while there is a specification for EXTCLK (20MHz), there is nothing in the electrical characteristics about the XTAL oscillator.  The only indication of maximum XTAL oscillator frequency is in the CLKSEL range setting, which indicates  the maximum range of 8.0 - 16.0 MHz.  So, per the datasheet, the only way to clock the 328PB @20 MHz is via an external clock source.  Seems a bit odd, doesn't it?

 

From the datasheet bookmarks.  No mention of the XTAL oscillator:

 

External clock spec:

 

 

 

EDIT: added while

 

The missing xtal mention in the datasheet is probably... a mis. But quite big, and quite... old now.

OTOH, the fuse spec of 8-16MHz is probably an artifact from the times when the max. freq. for this family was 16MHz.

 

 

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

sparrow2 wrote:
So it seem's that the chips are getting better !

Microchip Technology Inc

Microchip

Product Change Notification - JAON-09COJF091 - 20 Jun 2017 - CRS 15-1915 Final Notice: Implement silicon die revision C for ATMEGA328PB Atmel device families

http://www.microchip.com/mymicrochip/NotificationDetails.aspx?pcn=JAON-09COJF091

via http://www.microchip.com/mymicrochip/Reports.aspx?type=cpn&filter=ATmega328PB

though couldn't identify any silicon change for the low power crystal oscillator.

 

"Dare to be naïve." - Buckminster Fuller

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

No it's not an error in the datasheet, it's an error in the chip! (the 328PB are produced in an other proces where they can't get the "high" power crystal osc to work, now taken out of the data sheet).
The hole problem is that they are sold as 20MHz chips, but can't run that with either internal osc or crystal.

 

I assume they are made the in the same process as xtiny's and they get by because of an internal 20MHz osc. the 328PB don't have because they is a try to make a cheap 328P, and in many cases they actually are better and way cheaper.

 

   

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

sparrow2 wrote:
I assume they are made the in the same process as xtiny's ...
Yes

sparrow2 wrote:
... and in many cases they actually are better and way cheaper.
mega328PB is less expensive than mega328P.

https://octopart.com/search?q=ATmega328P&start=0&sort=median_price_1000&sort-dir=asc

 


Microchip Technology Inc

Microchip

Product Change Notification - GBNG-06LXXH156 - 11 Dec 2017 - CCB 2856 Initial Notice: Qualification of Microchip Fabrication site (FAB 4) for selected Atmel products manufactured with the 59.91K process technology.

http://www.microchip.com/mymicrochip/NotificationDetails.aspx?pcn=GBNG-06LXXH156

(open the affected CPN attachment, search for a MCU)

"Dare to be naïve." - Buckminster Fuller

Last Edited: Wed. Feb 21, 2018 - 09:26 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

So this board is twice as expensive as a similar board from Ali / Ebay

Then it's only for the "first 100 customers" marketing bullshit.

Then you have to go read the small letters for the shipping.

 

But I have to admit, The USD1.45 boards with free shipping from Ali /Ebay "only" hava an atmega168p on them.

https://www.aliexpress.com/wholesale?SearchText=Pro+Mini

 

Just for kicks I found one which claims to have an "mega328p" for USD 1.70 but I'm missing the "atmel" logo on the chip.

Has Microchip changed it?

 

And because these boards are more targeted to hobbyists then "professionals" the exact chip on the board won't matter much.

 

Paul van der Hoeven.
Bunch of old projects with AVR's:
http://www.hoevendesign.com

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 1

So this board is twice as expensive as a similar board from Ali / Ebay

Then it's only for the "first 100 customers" marketing bullshit.

 Yeah, but Pololu is a full-service vendor and a major designer/supplier to the hobbyist/etc robotics/etc community, with customer service, tutorials, and good documentation!  To be fair, you need to compare their prices to companies like Sparkfun, AdaFruit, Elektor, Solarbotics, and etc.  That might not always be worth "2x" over China, but it's probably worth a couple of bucks now and then.  ("Oh look: "a couple bucks" amounts to 2x in this case!")  (OTOH, you can get a 328PB Xplained Mini for about $10.  With mEDBG debugger.)

 

 

the exact chip on the board won't matter much.

I dunno.  The second UART on the PB is potentially REALLY useful.  And China doesn't seem to be shipping 328PBs yet.  I would have preferred a nano-like 328PB, but I have to admit that the "mini" is more consistent with Pololu's target audience.

 

OTTH, Pololu doesn't seem to publish their designs as OSHW, so clearly they're evil slime who should be boycotted!

 

Last Edited: Thu. Feb 22, 2018 - 02:49 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

westfw wrote:
OTTH, Pololu doesn't seem to publish their designs as OSHW, so ...
Watterott electronic's may be OSHW.

mega328 has a OSHW logo on the PCB plot

couldn't locate a license or copyright for the mega328PB board though it appears to have Eagle files (schematic, board) (oh ... OSHW logo in the board's picture)

https://github.com/watterott/wattuino#wattuino-pro-mini-pb

 

Edit: oh

 

"Dare to be naïve." - Buckminster Fuller

Last Edited: Thu. Feb 22, 2018 - 03:13 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 1

Hi, guys.

 

In case you're interested, Jan just posted a blog post addressing some of the points brought up in the last few comments:

 

https://www.pololu.com/blog/745/...

 

- Ben

 

Last Edited: Tue. Feb 27, 2018 - 02:58 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Pololu wrote:

Hi, guys.

 

In case you're interested, Jan just posted a blog post addressing some of the points brought up in the last few comments:

 

https://www.pololu.com/blog/745/...

 

- Ben

 

I've read the post.

Digikey still has the same politics about large quotes. Just asked them one moth ago about a quote for 1000 atmega88pb and got the same price as for 100.

And BTW, just check their price for atmega88pb. It is way lower than the Microchip's own price for 5K! (on the Microchip site).