// original code 
// https://projecthub.arduino.cc/mdraber/controlling-8x8-dot-matrix-with-max7219-and-arduino-0c417a

#include <SPI.h>
#define CS 7

// MAX7219 Control registers

#define DECODE_MODE   9 
#define INTENSITY     0x0A
#define SCAN_LIMIT    0x0B 
#define SHUTDOWN      0x0C
#define DISPLAY_TEST  0x0F

byte Apple [8]={B00011000,B00001000,B01110110,B11111111,B11111111,B11111111,B01111010,B00110100};

void   SendData(uint8_t address, uint8_t value) {  
  digitalWrite(CS, LOW);  // Start transfer, select chip
  SPI.transfer(address);  // Send address.
  SPI.transfer(value);    // Send the value.
  digitalWrite(CS, HIGH); // Finish transfer, unselect chip
}

void setup()   {
  pinMode(CS, OUTPUT);  
  SPI.setBitOrder(MSBFIRST);        // Most significant   bit first 
  SPI.begin();                      // Start SPI
  SendData(DISPLAY_TEST,  0x01);    // Run test - All LED segments lit.
  delay(1000);
  SendData(DISPLAY_TEST,  0x00);    // Finish test mode.
  SendData(DECODE_MODE,   0x00);    // Disable BCD mode. 
  SendData(INTENSITY,     0x0e);    // Use lowest intensity.   
  SendData(SCAN_LIMIT,    0x0f);    // Scan all digits.
  SendData(SHUTDOWN,      0x01);    // Turn on chip.
}

void loop()  {
  for (int i=1;i<9;i++)
    SendData(i, Apple[i-1]);
}