Availability of pins on Arduino Mega 2650

Hi,
I have a Mega with an Ethernet shield installed above it. I am now looking at extending my project and need either 12 or 16 input pins. I'm looking at using pins 14 - 21 and also 0 -7 (which pass through the ethernet card). How do I know if any of these pins are already assigned and therefore not available for me to use ?

Which Ethernet shield?

Railroader:
Which Ethernet shield?

To be honest, I can't remember which one it is ! It has a sticker on it with "Arduino", the Arduino symbol and "Ethernet shield". What other distinguishing details are there to identify it ?

Just looked at it again - it has the W5100 chip on it, if that helps.

buttimer:
How do I know if any of these pins are already assigned and therefore not available for me to use ?

Look it up on the schematic diagram of the board.
It seems only pin10 and the SPI pins are used by the shield.
All the analogue pins seem to be free.
Leo..

Can You check Your code for pin definitions and that way pick up pins being used? Maybe checking libraries used can tell in case a library is locking up I/O.

Wawa:
Look it up on the schematic diagram of the board.
It seems only pin10 and the SPI pins are used by the shield.
All the analogue pins seem to be free.
Leo..

Wawa:
Look it up on the schematic diagram of the board.
It seems only pin10 and the SPI pins are used by the shield.
All the analogue pins seem to be free.
Leo..

Can't seem to get to the schematic with that link.
I can avoid pin 10 easily enough. What pins are SPI on ?

Link works fine here.

SPI pins are different on an Uno or Mega.
Pin 50, 51, 52 on a Mega (linked to the 6-pin connector in the middle of the board).
Leo..