/*  7Segments 3LED with I2C-Master type Timer  BY M.K
    AT90S2313 4MHzOSC(ceramic resonator) 
    Last Mod 2012/4/24
    Used ROM (bytes): 1438  (70%):in I2C Contlor 750Byte
*/

// Software I2C connections
sbit Soft_I2C_Scl_Output    at PORTD0_bit;
sbit Soft_I2C_Sda_Output    at PORTD1_bit;
sbit Soft_I2C_Scl_Input     at PIND0_bit;
sbit Soft_I2C_Sda_Input     at PIND1_bit;
sbit Soft_I2C_Scl_Direction at DDD0_bit;
sbit Soft_I2C_Sda_Direction at DDD1_bit;

sbit Beep  at PORTD2_bit;         //Sound
//sbit SW    at PIND3_bit;        //SW in
sbit LED_0 at PORTD4_bit;
sbit LED_1 at PORTD5_bit;
sbit LED_2 at PORTD6_bit;
sbit dp    at PORTB7_bit;         //Decimal point


char     LED_Cunt,I2C_Cunt;
char     Cps,Csec,Cmin,Chour;
char     LED_0Data,LED_1Data;

void  To_7SegLED (char S_Data)
{
     switch(S_Data & 0x0f){
         case 0:
            PORTB=0x3f;
            break;
         case 1:
            PORTB=0x06;
            break;
         case 2:
            PORTB=0x5b;
            break;
         case 3:
            PORTB=0x4f;
            break;
         case 4:
            PORTB=0x66;
            break;
         case 5:
            PORTB=0x6d;
            break;
         case 6:
            PORTB=0x7d;
            break;
         case 7:
            PORTB=0x07;
            break;
         case 8:
            PORTB=0x7f;
            break;
         case 9:
            PORTB=0x6f;
            break;
         default:
           PORTB=0x08;
     }
}

void Read_Time(){
     Soft_I2C_Start();            // Issue start signal
     Soft_I2C_Write(0xA2);        // Address datasheet
     Soft_I2C_Write(2);           // Start from address 2
     Soft_I2C_Start();            // Issue repeated start signal
     Soft_I2C_Write(0xA3);        // read
     Csec = Soft_I2C_Read(1);     // Read seconds byte
     Cmin = Soft_I2C_Read(1);
     Chour= Soft_I2C_Read(0);
     Soft_I2C_Stop();
}

void Timer0_Interrupt() iv IVT_ADDR_TIMER0_OVF0
 {
     LED_Cunt++;
//
    if (LED_Cunt==1){             // **1
         LED_2=1;                 //OFF
         To_7SegLED(LED_0Data);
         LED_0=0;                 //ON
    // Timer
         I2C_Cunt++;
         if(I2C_Cunt >= 10){      // 4mSec*3*10 = 120mS
            I2C_Cunt=0;
            Read_Time();
         }
     }
    if (LED_Cunt==2){             // *1*
       LED_0=1;                   // OFF
       To_7SegLED(LED_0Data >>4);
       LED_1=0;                   // ON
//
        if (Csec==0){             // data in
            LED_0Data=Cmin;
            LED_1Data=Chour;
        }
     }
    if (LED_Cunt==3){             // 1**
       LED_Cunt=0;
       LED_1=1;                   //OFF
       To_7SegLED(LED_1Data);
       if ((Csec & 1)==1)
          dp=1;
       LED_2=0;                   //ON
     }
}

void main()
{
char       ic;
    DDRB = 0xFF;                  // 1=out
    PORTB= 0;
    DDRD = 0b11110100;            // 1=out 0=input 4.5.6=LED
    PORTD= 0b11111100;            // bit3=Pull UP          *
//
    LED_Cunt= 0;                  //I_Cunter Reset
    TCCR0 = 0x03;                 // 1/64=16uec
    TCNT0 = 0;                    // 16*256=4.096mSec
    TOIE0_bit=1;                  // Timer0      TIMSK = 2;
//
    Cps=0;                        //clear register
    Csec=0;
    Cmin=0;
    Chour=0;
          LED_0Data=Cmin;
          LED_1Data=Chour;
          Delay_ms(100);
    Soft_I2C_Init();              // Initialize Soft I2C communication
    //
    SREG_I_bit = 1;               // Interrupt on     asm   sei;
    //
    while(1){
      // Beep check
      if ((Cmin==0)||(Cmin==0X30)){    // 30 minute
         if (Csec==1){                 // 1Sec
             for (ic=0;ic<250;ic++){
                 Beep=~Beep;
                 Delay_us(200);        //2.5KHz
             }
             Beep=0;
             Delay_ms(220);
         }
      }
    }
}