PIC Vietnam - 9356SPI.C trouble?

Sao ko bo dau duoc vay ta? Cac huynh chiu kho doc khong dau nhe. De doc trong file library cua spi thay co vai diem la la nen hoi may huynh ti
Code:
///////////////////////////////////////////////////////////////////////////

////   Library for a MicroChip 93C56 configured for a x8 org           ////

////   Uses hardware SSP unit.                                         ////

////                                                                   ////

////   init_ext_eeprom();    Call before the other functions are used  ////

////                                                                   ////

////   write_ext_eeprom(a, d);  Write the byte d to the address a      ////

////                                                                   ////

////   d = read_ext_eeprom(a);   Read the byte d from the address a    ////

////                                                                   ////

///////////////////////////////////////////////////////////////////////////

////        (C) Copyright 1996,2003 Custom Computer Services           ////

//// This source code may only be used by licensed users of the CCS C  ////

//// compiler.  This source code may only be distributed to other      ////

//// licensed users of the CCS C compiler.  No other use, reproduction ////

//// or distribution is permitted without written permission.          ////

//// Derivative programs created using this software in object code    ////

//// form are not restricted in any way.                               ////

///////////////////////////////////////////////////////////////////////////



#define EEPROM_SELECT PIN_B0

#define EEPROM_DI     PIN_C5

#define EEPROM_DO     PIN_C4

#define EEPROM_CLK    PIN_C3



#define EEPROM_ADDRESS BYTE

#define EEPROM_SIZE    256





void init_ext_eeprom() {

   short int i;



   output_low(EEPROM_DI);

   output_low(EEPROM_CLK);

   output_low(EEPROM_SELECT);

   i=input(EEPROM_DO);



   setup_spi(SPI_MASTER | SPI_H_TO_L | SPI_CLK_DIV_16);



   output_high(EEPROM_SELECT);

   spi_write(0x9);           //hai hang nay    ????????

   spi_write(0x80);         // dung de lam gi ????????

   output_low(EEPROM_SELECT);

}





void write_ext_eeprom(EEPROM_ADDRESS address, BYTE data) {



   output_high(EEPROM_SELECT);  //sao lai keo len 1 vay ta??

   spi_write(0xa);

   spi_write(address);

   spi_write(data);

   output_low(EEPROM_SELECT);

   delay_ms(11);

}





BYTE read_ext_eeprom(EEPROM_ADDRESS address) {

   BYTE data;



   output_high(EEPROM_SELECT);//day nua lai keo len 1

   spi_write(0x18);

   spi_write(address);

   data=spi_read(0);

   output_low(EEPROM_SELECT);



   return(data);

}