MEGA XCK pins unmapped?


I wanted to use UART 1,2,3 in Synchronous mode (USART) but I see that all the XCK pins on the Atmega2560 are unmapped.

Does anyone know why this is? Is there something worng/bad about using USART on the MEGA?

Is there any way to get around this constraint?

Cheers, Bob

I don't know what the reason was for Arduino not mapping those pins but there is a 3rd party hardware package that maps all pins on the ATmega2560: After installing you just need to select Tools > Board > ATmega2560 and then Tools > Pinout > AVR pinout.

Note that support for ATmega2560 and other 100 pin AVRs is only available in this beta branch of MegaCore (though close to being released) and has not been included in any of the official releases yet so you need to follow the manual installation instructions, you can't do a Boards Manager installation yet.


Thanks for that super useful post!!! I will try it and post back the results!!!

Cheers, Bob

I'm glad if it can be helpful to you. Please report if you find any bugs. The 100 pin chips are a relatively new addition to MegaCore so they haven't been tested quite so thoroughly as the 64 pin chips that made up the original MegaCore but we have been doing a lot of work to get it ready for a release so I think it should work for you.


I'll be working with it tomorrow and over the weekend.

Sadly, I don't have much expertise in low level hardware programming, even if all I need to do is:

pinMode(39,OUTPUT); // PD5 == XCK1
pinMode(15,OUTPUT); // PB0 == SS ??

// then as needed:

digitalWrite(15, LOW);

I will post back any results!

Thanks so much! Bob

I offer a couple of designs that break out all the pins if you need that |500x316


And a DIP version that hasn't made it on my website yet |500x190 More details at this topic