can I make any other digital pin of the mega an SS pin,while pin 53 is still SS

Projects Programming
1 
[/code  #include <SD.h>
 #include <SPI.h>
   
 //TO TEST IF MY SD CARD IS COMMUNICATING WITH MY ARDUINO
 //For Arduino MEGA
 //MOSI to pin 51
 //MISO to pin 50
 //CLK(SCK) to pin 52
 //CS(SS) to pin 53
 //pow pin = 8
int SS_pin = 35; 
 int pow_pin = 8;
 void setup()
 
 {
  pinMode(SS_pin,  OUTPUT); 
 
  pinMode(pow_pin, OUTPUT);
 
  SPI.begin(); 
  Serial.begin(9600);
  Serial.println("initializing card.....Please wait");
   
   //check if card is ready
 
   if(!SD.begin(SS_pin))
   
   {
     Serial.println("CARD FAILURE");
     return;
   }

Serial.println("CARD IS READY");
 }
 
 void loop()
 {
 digitalWrite(pow_pin, HIGH);  //SET POWER PIN
 digitalWrite(SS_pin, LOW);
 
 String dataString = "my name is OKECHUKWU KINGDOM-MELODY. I am feeling good because my SD card test is responding properly. Cheer with me";
   
   //open a file to write, only 1 file can open at a time
   
   File dataFile = SD.open("log.txt", FILE_WRITE);
   if(dataFile)
   {
     dataFile.println(dataString);
     dataFile.close();
     Serial.println(dataString);
   }
      else
      {
        Serial.println("FILE COULD NOT BE OPENED");
      }
      
   delay(5000);//5 seconds delay
 }
   ]
2

Yes you can. In fact you must if you have more than 1 SPI device.

3

The SS pin must be an output for your device to be SPI master. If you set it to an input and it gets taken low, the device will go into SPI slave mode.