Arduino nano & pro micro SPI simple communication
void setup() {
// put your setup code here, to run once:
 Serial.begin(9600);//start Serial
 Serial.println("Setting Up");
 void SPI_Init(void);   // &lt;---------------- this is wrong!
 delay(100);
 Serial.println("SPI intialization is complete");
 }



That isn't how you call a function.

It should read:

SPI_Init ();