#include <SPI.h>

volatile int spi_receiver = 0;

void setup() {
  Serial.begin(9600);
  pinMode(MISO, OUTPUT);
  SPCR |= _BV(SPE);
  SPI.attachInterrupt();
}

ISR(SPI_STC_vect) {
  spi_receiver = SPDR;
  SPDR = 200;
}

void loop() {
  Serial.println(spi_receiver);
  delay(1000);
}