x25045.c

自己keil C51写的X25045驱动

#define  WREN  0x06    /* Set the write enable latch(enable write operations)       */
#define  SFLB  0x00    /* Set flag bit                                              */
#define  WRDI  0x04    /* Reset the write enable latch/reset flag bit               */
#define  RSDR  0x05    /* Read status register                                      */
#define  WRSR  0x01    /* Write status register                                     */
#define  READ  0x03    /* Read data from memory array beginning at selacted address */
#define  WRITE 0x02    /* Write data to memory array beginning at selacted address  */


char byte_read_eeprom(unsigned char address){
   unsigned char i,command;



   EEPROMCS = 0;
   command  = READ;
     
   for(i=0;i<8;i++){
     SCLK = 0;
     if(command & 0x80) SI = 1;
        else SI = 0;
     command = (command << 1);
     SCLK = 1;  
   }
  
   for(i=0;i<8;i++){
     SCLK = 0;
     if(address & 0x80) SI = 1;
        else SI = 0;
     address = (address << 1);
     SCLK = 1;  
   }
   
   for(i=0;i<8;i++){
     SCLK = 0;
     _nop_();
     command = (command << 1) | SO;
     SCLK = 1;
   } 

   EEPROMCS = 1; 

   return command;
}


char read_status(){
   unsigned char i,command;


   EEPROMCS = 0;
   command  = RSDR;
     
   for(i=0;i<8;i++){
     SCLK = 0;
     if(command & 0x80) SI = 1;
        else SI = 0;
     command = (command << 1);
     SCLK = 1;  
   }

   for(i=0;i<8;i++){
     SCLK = 0;
     _nop_();
     command = (command << 1) | SO;
     SCLK = 1;
   } 

   EEPROMCS = 1;

   return command;
}


void write_status(char status){
   unsigned char i,command;


   EEPROMCS = 0;
   command  = WRSR;
     
   for(i=0;i<8;i++){
     SCLK = 0;
     if(command & 0x80) SI = 1;
        else SI = 0;
     command = (command << 1);
     SCLK = 1;  
   }

   command = status;
   for(i=0;i<8;i++){
     SCLK = 0;
     if(command & 0x80) SI = 1;
        else SI = 0;
     command = (command << 1);
     SCLK = 1;  
   } 

   EEPROMCS = 1;
}


write_enable_latch(){
   unsigned char i,command;


   EEPROMCS = 0;
   command  = WREN;
     
   for(i=0;i<8;i++){
     SCLK = 0;
     if(command & 0x80) SI = 1;
        else SI = 0;
     command = (command << 1);
     SCLK = 1;  
   }

   EEPROMCS = 1;
}


byte_write_eeprom(unsigned char address,char wdata){
   unsigned char i,command;

   write_enable_latch();

   EEPROMCS = 0;
   command  = WRITE;
     
   for(i=0;i<8;i++){
     SCLK = 0;
     if(command & 0x80) SI = 1;
        else SI = 0;
     command = (command << 1);
     SCLK = 1;  
   }
  
   for(i=0;i<8;i++){
     SCLK = 0;
     if(address & 0x80) SI = 1;
        else SI = 0;
     address = (address << 1);
     SCLK = 1;  
   }

   command = wdata;
   for(i=0;i<8;i++){
     SCLK = 0;
     if(command & 0x80) SI = 1;
        else SI = 0;
     command = (command << 1);
     SCLK = 1;  
   }  

   EEPROMCS = 1;
}