I just had a look at the pins used by the Ethernet SD shield (the currently latest version) and found this documentationhttp://www.arduino.cc/playground/Main/ShieldPinUsage
where it says that the shield uses pins 10, 11, 12, 13.
However, in the introduction of the shieldhttp://arduino.cc/en/Main/ArduinoEthernetShield
"Arduino communicates with both the W5100 and SD card using the SPI bus (through the ICSP header). This is on digital pins 11, 12, and 13
on the Duemilanove..."
"If you're not using one of the peripherals in your program, however, you'll need to explicitly deselect it. To do this with the SD card, set pin 4
as an output and write a high to it. For the W5100, set digital pin 10
as a high output."
So if I understand this correctly, pins 4 and 10 are used to turn either the SD part or the ethernet part on or off.
So if pin 10 per definition is a used one, shouldn't be pin 4 declared as used too?
The question came up because I'm running out of pins soon and have to start bean counting.