sbit DS_CLK = P1^6;
            sbit DS_IO = P1^5;
            sbit DS_RST = P1^4;
            /********************************************
            * Shift Data from Mcu in DS1302 *
            ********************************************/
            void DS_Shift_In(unsigned char bIn)
            {
            unsigned char i;
            for( i=0;i<8;i++ )
            {
            DS_CLK = 0; /* low logic level */
            if( bIn&0x01 ) DS_IO = 1; /* change data */
            else DS_IO = 0; /* LSB first */
            bIn = bIn>>1; /* next bit */
            DS_CLK = 1; /* raising edge in */
            _nop_(); /* delay */
            _nop_();
            } 
            }
            /********************************************
            * Shift Data from DS1302 to MCU *
            ********************************************/
            unsigned char DS_Shift_Out(void)
            {
            unsigned char i, bData;
            DS_IO=1; /* release DS_IO */ 
            for( i=0;i<8;i++ )
            {
            DS_CLK = 1; /* high logic level */
            _nop_(); /* delay */
            _nop_();
            DS_CLK = 0; /* failing edge data removed */
            _nop_(); /* delay */
            _nop_();
            bData = bData>>1; /* store data */
            if( DS_IO ) bData = bData|0x80 ;
            } 
            return (bData);
            }
            /********************************************
            * Read One Byte from DS1302 to MCU *
            * Written in 25/10,2000. HIT *
            * cr: Read Command * 
            * 0x81-Read Second: CH XXX,XXXX(BCD) *
            * 0X83-Read Minute: 0 XXX,XXXX(BCD) * 
            * 0X85-Read Hour: 12/24 0 A/P x,xxxx * 
            * 0X87-Read Date: 00 XX,XXXX(BCD) * 
            * 0X89-Read Month: 000 X,XXXX(BCD) * 
            * 0X8B-Read Week: 00000 XXX(BCD) * 
            * 0X8D-Read Year: xxxx XXX(BCD) * 
            ********************************************/
            unsigned char DS_Read( unsigned char cr )
            {
            unsigned char dd=0;
            DS_RST = 0; /* initializing */
            _nop_(); 
            DS_CLK = 0; /* SCLK low logic level */
            _nop_();
            DS_RST = 1; /* Enabled */
            DS_Shift_In( cr ); /* Write Command Byte */
            dd = DS_Shift_Out(); /* Read Data */
            DS_RST=0; /* Disabled */
            DS_CLK=1; 
            return ( dd );
            }
            /*********************************************
            * Read One Byte from DS1302 to MCU *
            * Written in 25/10,2000. HIT *
            * ord: Write Command,dd-data for writting* 
            * 0x80-Write Second: CH XXX,XXXX(BCD) *
            * 0X82-Write Minute: 0 XXX,XXXX(BCD) * 
            * 0X84-Write Hour: 12/24 0 A/P x,xxxx * 
            * 0X85-Write Date: 00 XX,XXXX(BCD) * 
            * 0X86-Write Month: 000 X,XXXX(BCD) * 
            * 0X8a-Write Week: 00000 XXX(BCD) * 
            * 0X8c-Write Year: xxxx XXX(BCD) * 
            *********************************************/
            void DS_Write(unsigned char ord,unsigned char dd)
            {
            DS_RST = 0;
            _nop_();
            DS_CLK = 0;
            _nop_();
            DS_RST = 1; /* Enable */
            DS_Shift_In( ord ); /* Write Command */
            DS_Shift_In( dd ); /* Write Data */
            DS_RST = 0;
            DS_CLK = 1;
            }
            /*********************************************
            * Set DS1302 Clock Value *
            * Written in 25/10,2000. HIT *
            * dt[6]-dt[0]: Week,Year,Month,Date * 
            * Hour,Minute,Second * 
            *********************************************/
            void DS_SetClock(unsigned char dt[7])
            {
            DS_Write(0x8E,0); /* Disabled Write Protect */
            DS_Write(0x80,0x80); /* Disabled Clock */
            DS_Write(0x8a,dt[6]); /* Week Day BCD */ 
            DS_Write(0x8c,dt[5]); /* Year : BCD */ 
            DS_Write(0x88,dt[4]); /* Month : BCD */ 
            DS_Write(0x86,dt[3]); /* Date : BCD */ 
            DS_Write(0x84,dt[2]); /* Hour(24) BCD */ 
            DS_Write(0x82,dt[1]); /* Minute : BCD */ 
            DS_Write(0x80,dt[0]&0x7F); /* Second : BCD */
            /* MSB:0 Enabled Clock */ 
            DS_Write(0x8E,0x80); /* Enabled Write Protect */
            }
            /*********************************************
            * Read DS1302 Clock Value *
            * Written in 25/10,2000. HIT *
            * dt[6]-dt[0]: Week,Year,Month,Date * 
            * Hour,Minute,Second * 
            *********************************************/
            void DS_ReadClock(unsigned char dt[7])
            {
            dt[6]=DS_Read(0x8b);      /* Week */ 
            dt[5]=DS_Read(0x8d);      /* Year */ 
            dt[4]=DS_Read(0x89);      /* Month */ 
            dt[3]=DS_Read(0x87);      /* Date */ 
            dt[2]=DS_Read(0x85)&0x3F; /* Hour */ 
            dt[1]=DS_Read(0x83)&0x7F; /* Minute */ 
            dt[0]=DS_Read(0x81)&0x7F; /* Second */
            }