Mega with wiznet shield (wire hack)+thingspeak+sd problem

Using Arduino Programming Questions
75

Just to be sure...pin definition and enable/disable 'devices'...
So I'm using the realtime clock, onewire( digital pin3), sd card( digital pin8), and wiznet (digital pin 10). Shield has no ICSP connection.

Please confirm, I should enable/disable the devices.

inputs and outputs : sdcard( 8 ), wiznet(10) and onewire (3) should be defined as an output, is it right? ( on onewire currently there are 3 ds18b20 )
enable/disable: put the pin to LOW state will enable the 'device', put the pin to HIGH state will disable that. Is it right?

for example here before I should enable wiznet, and disable SD and onewire:

//in the setup()

pinmode(8,OUTPUT);
pinmode(10,OUTPUT);
pinmode(3,OUTPUT);


//in loop() for example


digitalwrite(10,LOW);
digitalwrite(8,HIGH);
digitalwrite(3,HIGH);

if(!getPage(server,pageAdd)) Serial.print("Fail ");
    else Serial.print("Pass ");

Are these correct?