328PB sometimes worse than 328P

For my "pocket calculator" I have been using the UNO plus QYT-TM1638 (16 keys+8 digits). To reduce the size I replaced the UNO by a NANO. Actually, it was a NANO equipped with the ATmega328PB. Installing and uploading was no problem (json found at Pololu, works pretty well). But running the NANO with the QYT module lead to instability and a burst of restarts no matter where and how many capacitors I added. I even set the brightness to 1 but no improvement. Of course, I did not make use of any of the 328PB extended features. So, at the end of the day I replaced the 328PB NANO by a 328P (no B!) NANO, and everything worked fine, even with maximum brightness. My only explanation is: in the 328PB version they dropped some of the power pins to get more I/O pins. So possibly it is less robust in an environment where some spikes on the supply power might occour.

The UNO has more program space than a NANO. ~1.5K , Whats the memory usage of your program? Do you get "Low memory available, stability problems may occur." after you compile your program? Watch this

https://www.youtube.com/watch?v=bpXUvRr2ywA

Also what pins on the NANO are you using?

Klausj:
For my “pocket calculator” I have been using the UNO plus QYT-TM1638 (16 keys+8 digits). To reduce the size I replaced the UNO by a NANO. Actually, it was a NANO equipped with the ATmega328PB. Installing and uploading was no problem (json found at Pololu, works pretty well). But running the NANO with the QYT module lead to instability and a burst of restarts no matter where and how many capacitors I added. I even set the brightness to 1 but no improvement. Of course, I did not make use of any of the 328PB extended features. So, at the end of the day I replaced the 328PB NANO by a 328P (no B!) NANO, and everything worked fine, even with maximum brightness.
My only explanation is: in the 328PB version they dropped some of the power pins to get more I/O pins.
So possibly it is less robust in an environment where some spikes on the supply power might occour.

Welcome to the “improved” 328pb AVR which now lacks a full swing oscillator making it as unstable as

edit: Sorry, never intended to offend the 328pb! :slight_smile:

typematrix: The UNO has more program space than a NANO. ~1.5K , Whats the memory usage of your program? Do you get "Low memory available, stability problems may occur." after you compile your program? Watch this

https://www.youtube.com/watch?v=bpXUvRr2ywA

Also what pins on the NANO are you using?

Since when does a 328p have less program memory than a 328p? And, "low" progmem will not affect stability. Low SRAM might, but not low flash...

The UNO has more program space than a NANO. ~1.5K

Since when does a 328p have less program memory than a 328p?

The Uno sets fuses for the 512b optiboot bootloader, while the Nano still sets them for a 2k bootloader.

westfw: Since when does a 328p have less program memory than a 328p? The Uno sets fuses for the 512b optiboot bootloader, while the Nano still sets them for a 2k bootloader.

I did not know that. I have several Nano 3.0 boards, but first thing I did with them was flash my own (512 byte) bootloader into them. My boards.txt file also has them set as 512 byte (fuse-wise and max progmem-wise).

Never noticed the difference.

If the board is resetting, I would argue that that is a problem with the 328pb nano you got. I have boards based on the 328pb that are rock-solid stable.

And +1 to bootloading 328p nanos (and pro mini's) as uno