#include <SPI.h>

static const int g_iBaudrate = 40000000; 
SPIClass* hspi = nullptr;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);

  // Init SPI
  hspi = new SPIClass( HSPI );
  hspi->begin( 14, 12, 13, 27 );  // Set pins. CLK(SCK):14, MISO:12, MOSI:13, SS:27
  pinMode( hspi->pinSS(), OUTPUT );
  digitalWrite( hspi->pinSS(), HIGH );
  
  // Init MAX7219 register
  sendSPICmd( hspi, 0x9, 0 ); // Decode Mode:0 (Address:0x9, Data:0)
  sendSPICmd( hspi, 0xA, 6 ); // Intensity:6 (Address:0xA, Data:6)
  sendSPICmd( hspi, 0xB, 7 ); // Scan Limit:7(8 lines) (Address:0xB, Data:7)
  sendSPICmd( hspi, 0xC, 1 ); // ShutDown:1 (Address:0xC, Data:1)
  sendSPICmd( hspi, 0xF, 0 ); // Display Test:0 (Address:0xF, Data:0)
}

void loop() {
  // put your main code here, to run repeatedly:
  // Display LED
  for( int i = 1; i <= 8; ++i )
  {
    if( i == 1 || i == 8 )
      sendSPICmd( hspi, i, 255 );
    else
      sendSPICmd( hspi, i, 129 );
  }

  delay(200);

  for( int i = 1; i <= 8; ++i )
  {
    if( i == 1 || i == 8 )
      sendSPICmd( hspi, i, 0 );
    else if( i == 2 || i == 7 )
      sendSPICmd( hspi, i, 126 );
    else
      sendSPICmd( hspi, i, 66 );
  }

  delay(200);

  for( int i = 1; i <= 8; ++i )
  {
    if( i == 1 || i == 2 || i == 7 || i == 8 )
      sendSPICmd( hspi, i, 0 );
    else if( i == 3 || i == 6 )
      sendSPICmd( hspi, i, 60 );
    else
      sendSPICmd( hspi, i, 36 );
  }

  delay(200);

  for( int i = 1; i <= 8; ++i )
  {
    if( i == 4 || i == 5 )
      sendSPICmd( hspi, i, 24 );
    else
      sendSPICmd( hspi, i, 0 );
  }

  delay(200);
}

void sendSPICmd( SPIClass* spi, byte byReg, byte byBuf )
{
  spi->beginTransaction( SPISettings( g_iBaudrate, MSBFIRST, SPI_MODE0 ) );
  digitalWrite( hspi->pinSS(), LOW );  // Start communicate
  spi->transfer( byReg );
  spi->transfer( byBuf );
  digitalWrite( hspi->pinSS(), HIGH );  // Stop communicate
  spi->endTransaction();
}