AVR Segment + DotMatrix with 74HC595

/*
 * ATMega8_Uhr_mit_Schieberegistern.c
 *
 * Created: 12.04.2013 11:50:12
 *  Author: Alexander Brysch
 */

#define F_CPU 16000000UL
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>

#define SHIFT_REGISTER DDRB
#define SHIFT_PORT PORTB
#define DATA  (1<<PB3)     // MOSI (SI)
#define LATCH (1<<PB2)     // SS   (RCK)
#define CLOCK (1<<PB5)     // SCK  (SCK)
#define INITLED (1<<PB1)

unsigned int SekundenEiner = 0;
unsigned int SekundenZehner = 0;
unsigned int MinutenEiner = 0;
unsigned int MinutenZehner = 0;
unsigned int StundenEiner = 0;
unsigned int StundenZehner = 0;

unsigned int LEDON = 0;
unsigned int DOT = 0;
unsigned int x=0;


void init_IO(void)
{
  SHIFT_REGISTER |= (DATA | LATCH | CLOCK | INITLED);   // SET Control Pins as Output
  DDRD |= (1<<PD2);
  SHIFT_PORT &= ~(DATA | LATCH | CLOCK | INITLED);      // SET Control Pins low
}

void init_SPI(void)
{
  SPCR = (1<<SPE) | (1<<MSTR);                          // Start SPI as Master
}

void spi_send(unsigned char data0, unsigned char data1, unsigned char data2, unsigned char data3, unsigned char data4)
{
  SPDR = data0;
  while(!(SPSR & (1<<SPIF)));   //Wait for SPI process to finish
  SPDR = data1;
  while(!(SPSR & (1<<SPIF)));   //Wait for SPI process to finish
  SPDR = data2;
  while(!(SPSR & (1<<SPIF)));   //Wait for SPI process to finish
  SPDR = data3;
  while(!(SPSR & (1<<SPIF)));   //Wait for SPI process to finish
  SPDR = data4;
  while(!(SPSR & (1<<SPIF)));   //Wait for SPI process to finish
  SHIFT_PORT |= LATCH;
  SHIFT_PORT &= ~LATCH;
}

void reset_Shift()
{
  spi_send(0b00000000, 0b00000000, 0b00000000, 0b00000000, 0b00000000);
  SHIFT_PORT |= LATCH;
  SHIFT_PORT &= ~LATCH;
}

uint8_t timer_start()
{
  TIMSK = (1<<OCIE1A);
  sei();  // Enable Interupts
  return 0;
}

void timer_stop()
{
  TIMSK = (0<<OCIE1A); // Disable Timer 0
  cli(); // Disable Interupts
}

ISR(TIMER1_COMPA_vect)
{
  if(DOT == 0)
  {
    DOT = 1;
    SekundenEiner++;
    LEDON=1;
    PORTB |= INITLED; // Turn LED ON
  }else{
    DOT = 0;
  }
}

// INTERRUPT
ISR(INT0_vect)
{
  timer_stop();
  SekundenEiner = 0;
  SekundenZehner = 0;
  MinutenEiner = 0;
  MinutenZehner = 0;
  StundenEiner = 0;
  StundenZehner = 0;
  timer_start();
  GIFR |= (1<<INTF0);

}

int main(void)
{

  init_IO();
  init_SPI();
  reset_Shift();
  _delay_ms(500);

  TCCR1B |= (1 << WGM12);                //CTC Modus
  TCCR1B |= (1 << CS12) | (0 << CS11) | (0 << CS10);   //Prescaler Clock / 256
  //OCR1A = 61250; // 1000 MS                     //Compare Wert setzen
  OCR1A = 30625; // 500 MS


  // Interrupt Start
  GIMSK |= (1<<INT0);
  //PCMSK |= (1<<INT0);
  MCUCR |= (1<< ISC01) | (1<<ISC00);
  timer_start();
  // Interrupt Stop

  char Segment_Zahlen[10] =
  { //   DPgfedcba
    // 0b 00000001,
    0b11000000, // 0 a, b, c, d, e, f
    0b11111001, // 1 b,c
    0b10100100, // 2 a, b, d e,  g
    0b10110000, // 3 a, b,c, d g,
    0b10011001, // 4 , b,cf g,
    0b10010010, // 5 a,c, d f, g,
    0b10000010, // 6 acdefg
    0b11111000, // 7 abc
    0b10000000, // 8 abcdefg
    0b10010000 // 9 abcdfg
  };
  char Segment_DOTZahlen[10] =
  { //   DPgfedcba
    // 0b 00000001,
    0b01000000, // 0 a, b, c, d, e, f
    0b01111001, // 1 b,c
    0b00100100, // 2 a, b, d e,  g
    0b00110000, // 3 a, b,c, d g,
    0b00011001, // 4 , b,cf g,
    0b00010010, // 5 a,c, d f, g,
    0b00000010, // 6 acdefg
    0b01111000, // 7 abc
    0b00000000, // 8 abcdefg
    0b00010000 // 9 abcdfg
  };

  char Segment_Masse[4] = {
    0b00010000,
    0b00100000,
    0b01000000,
    0b10000000
  };
  char Matrix_Zahlen[10][5] =
  {
    { 0b01110000, 0b01010000, 0b01010000, 0b01010000, 0b01110000 }, // 0
    { 0b00100000, 0b01100000, 0b00100000, 0b00100000, 0b01110000 }, // 1
    { 0b01110000, 0b00010000, 0b01110000, 0b01000000, 0b01110000 }, // 2
    { 0b01110000, 0b00010000, 0b01110000, 0b00010000, 0b01110000 }, // 3
    { 0b01010000, 0b01010000, 0b01110000, 0b00010000, 0b00010000 }, // 4
    { 0b01110000, 0b01000000, 0b01110000, 0b00010000, 0b01110000 }, // 5
    { 0b01110000, 0b01000000, 0b01110000, 0b01010000, 0b01110000 }, // 6
    { 0b01110000, 0b00010000, 0b00010000, 0b00010000, 0b00010000 }, // 7
    { 0b01110000, 0b01010000, 0b01110000, 0b01010000, 0b01110000 }, // 8
    { 0b01110000, 0b01010000, 0b01110000, 0b00010000, 0b01110000 } // 9
  };

  char Matrix_Masse[5] = {
    0b11110000, // Zeile 1
    0b11101000, // Zeile 2
    0b11011000, // Zeile 3
    0b10111000, // Zeile 4
    0b01111000  // Zeile 5
  };
  while(1)
  {
    if(LEDON==1) { PORTB &= ~INITLED; }
    if (SekundenEiner>9) { SekundenEiner = 0; SekundenZehner++; }
    if (SekundenZehner > 5) { SekundenZehner = 0; MinutenEiner++; }
    if (MinutenEiner>9) { MinutenEiner=0; MinutenZehner++; }
    if (MinutenZehner>5) { StundenEiner++; MinutenZehner=0; }
    if (StundenEiner>9) { StundenZehner++; StundenEiner=0; }
    if (StundenZehner>9) { StundenZehner=0; }
    SHIFT_PORT &= ~LATCH;
    for (x=0; x<5; x++)
    {
      spi_send(Matrix_Masse[x], Matrix_Zahlen[SekundenEiner][x], Matrix_Zahlen[SekundenZehner][x], 0b00000000, 0b00000000);
    }
    spi_send(0b00000000, 0b00000000, 0b00000000, Segment_Masse[0], Segment_Zahlen[MinutenEiner]);
    spi_send(0b00000000, 0b00000000, 0b00000000, Segment_Masse[1], Segment_Zahlen[MinutenZehner]);
    if(DOT == 1)
    {
      spi_send(0b00000000, 0b00000000, 0b00000000, Segment_Masse[2], Segment_DOTZahlen[StundenEiner]);
    }else{
      spi_send(0b00000000, 0b00000000, 0b00000000, Segment_Masse[2], Segment_Zahlen[StundenEiner]);
    }
    spi_send(0b00000000, 0b00000000, 0b00000000, Segment_Masse[3], Segment_Zahlen[StundenZehner]);
  }
  return 0;
}