Arduino Schematics

Hello:
Is there an official repository for the Arduino boards’ schematics and pinouts? For now I am looking for the older Arduino Uno, Nano, Pro Mini and Mega schematics.

Also should the code written for one board, such as the Uno, also work without any conversion on another board, such as the Nano?

Thank you for your guidance!

10toes1962:
Is there an official repository for the Arduino boards’ schematics

Unfortunately, the schematics are not stored in a public repository. You can download them from the product pages on the Arduino Store.

For previous versions of the schematics, try the Wayback Machine. It looks like you can get schematics going all the way back to 2006 by following the links off the home page:
http://web.archive.org/web/20060118051045/http://www.arduino.cc:80/
Note that the more specific page URLs have changed over time, so follow the links off the home page if you find the history for a subpage cuts off unexpectedly.

10toes1962:
pinouts?

The pin definitions are here:

That content was moved from the IDE repository some years ago:

I believe they tried to migrate as much of the commit history as possible, but it might not go all the way back, so you might need to look through the arduino/Arduino repo's history for very old versions of the variants files.

10toes1962:
Also should the code written for one board, such as the Uno, also work without any conversion on another board, such as the Nano?

In the case of Uno to Nano, no conversion is necessary, since these boards both use the ATmega328P. In other cases, where you are switching from one microcontroller to another, you might need to make some changes. Due to the standardized Arduino API, in many cases, an Arduino sketch is able to work on any board. It just depends on whether there is hardware-specific code.

What a fantastic response! I owe you a car wash!! Thank you!

You're welcome. I'm glad if I was able to be of assistance. Enjoy!
Per