Interface program between clock chip DS1302 and MCS51 microcontroller C51

#pragma small
#include
#include

/********************************************
* DS1302 PIN Configuration *
********************************************

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 */
}