ATmega328 drop-in replacement with more flash memory

Question

Is there a ATmega328 drop-in replacement with more flash memory?

Needs to be 28 pin DIL to fit the socket.

Alternatively, is there a board that has the exact dimensions and pins as an Arduino UNO, but with more flash memory?

Everything in my project works fine, but I need more program memory. Can unfortunately not use a different board layout or size.

• the busybee: What did you try to find out? Did you visit the manufacturer's web site? Did you visit Arduino's web site for other models?
• Cowboy_Patrick: Would it be possible for you to use an external flash memory? Something like the Macronix MX25R6435F.
• Björn Morén: @Cowboy_Patrick: Thanks for the suggestion, but unfortunately not.
• dandavis: the wemos D1 (not mini) has an uno form factor and a bajillion times more ram. it is 3.3v though. You probably could make a custom PCB with uno layout and an ESP32s2 and integrated logic level shifters. might be a useful project for many,
• Björn Morén: @dandavis Thanks, great suggestion. I looked at the Wemos D1 a few weeks ago, and if it had 5 V logic levels, it would be the board for me. I was hoping to get away with not making a custom PCB.

Answer 1

Is there a ATmega328 drop-in replacement with more flash memory?

No

Alternatively, is there a board that has the exact dimensions and pins as an Arduino UNO, but with more flash memory?

Yes, but it'll be probably something with ARM (UNO R4 minima has even 5V ARM), However libraries might be an issue

As for AVRs, there are for example AVR128DA28 but as far as I know, it's definitely not pin compatible.

However you could use some proto board for UNO and wire it up somehow on it. (128kB, 28pin).

Also Atmega644/1284 (in pdip 40) could be used on proto board and it's much more compatible

• Björn Morén: Thanks, great answer. Will probably get the UNO R4 minima.
• KIIV: Well then aware it doesn't have such strong output drivers (8mA tops), mentioned libraries compatibility and it's relatively new, so even bugs in arduino core are possible