Basic MEGA pins question

Using Arduino Microcontrollers
1

Everyone!

I just started using my MEGA1280 for a prototype work. I am learning my MEGA speak now.

Arduino official site says MEGA has 54 digital pins and 16 analog pins. So a total of 70 independent pins, correct?
The Atmel Doc2549 says 86 programmable I/O lines for MEGA640/1280/2560. Does this mean some of the I/O lines are not brought out on MEGA1280/2560?

Just want to know all my pins :grin: in case I need to use RuggedCircuit's MegaRAM shield.

Thank you!

2

liudr:
Everyone!

I just started using my MEGA1280 for a prototype work. I am learning my MEGA speak now.

Arduino official site says MEGA has 54 digital pins and 16 analog pins. So a total of 70 independent pins, correct?
The Atmel Doc2549 says 86 programmable I/O lines for MEGA640/1280/2560. Does this mean some of the I/O lines are not brought out on MEGA1280/2560?

Just want to know all my pins :grin: in case I need to use RuggedCircuit's MegaRAM shield.

Thank you!

Yes there are 16 pins that the arduino mega boards do not break out to any socket pins, no traces leaving those chip pins. The Seeeduino mega board (1280 based) does break out those additional 16 pins to an additional socket but I'm not sure the arduino core pins definition includes those 'extra' 16 I/O pin or not and if not you would have to use direct port access commands to read or write to them.

Lefty

3

Thank you Lefty! I should be alright with 56+16. Just be sure, the 16 analog pins can be used as digital pins, right?

What about the serial pins? Can I use serial ports 1-3 pins without getting into trouble?

4

liudr:
Thank you Lefty! I should be alright with 56+16. Just be sure, the 16 analog pins can be used as digital pins, right?

Yes
What about the serial pins? Can I use serial ports 1-3 pins without getting into trouble?

Yes, actually less troublesome then serial 0 as there is no USB serial converter wired to those pins.

5

retrolefty:

liudr:
Thank you Lefty! I should be alright with 56+16. Just be sure, the 16 analog pins can be used as digital pins, right?

Yes
What about the serial pins? Can I use serial ports 1-3 pins without getting into trouble?

Yes, actually less troublesome then serial 0 as there is no USB serial converter wired to those pins.

Thanks again. I may want to remove the instantiation of the serials 1-3 to save some 192 bytes of SRAM since I'm not using them.