#include int x; void setup() { Serial.begin(115200); SPI.begin(); SPI.setClockDivider(SPI_CLOCK_DIV8); digitalWrite(SS,HIGH); } void loop() { byte Mastersend,Mastereceive; digitalWrite(SS, LOW); x = 1; Mastersend = x; Mastereceive=SPI.transfer(Mastersend); if(Mastereceive == 1){ Serial.println("Master receive 1"); } else{ Serial.println("Master receive 0"); } }