#include <SPI.h>

void setup() {
  SPI.begin();
  pinMode(10, OUTPUT);
  digitalWrite(10, HIGH);
  Serial.begin(9600);
}

void loop() {
  digitalWrite(10, LOW);
  byte response = SPI.transfer(0x42);
  digitalWrite(10, HIGH);

  Serial.print("Received: ");
  Serial.println(response);
  delay(1000);
}