Data processing device

Abstract

A data processing device includes a read-only memory, a flash memory capable of modifying information stored therein and adding information thereto, a central processing unit performing data processing using information stored in the read-only memory and the flash memory, an information storage area provided in the flash memory for storing predetermined modifiable information among the information used by the central processing unit for data processing, an address storage area provided in the flash memory for storing at least the address of information stored in the information storage area, and an address-modification control unit for, after at least one of modification of modifiable information stored in the information storage area and addition of modifiable information to the information storage area is performed, performing modification of the address of the information stored in the address storage area or addition of the address of the information to the address storage area, whereby the information of the central processing unit used for data processing can be freely modified or added.

What is claimed is:  
     
         1 . A data processing device comprising: 
 a read-only memory;    a flash memory capable of modifying information stored therein and adding information thereto;    a central processing unit performing data processing using information stored in said read-only memory and said flash memory;    an information storage area provided in said flash memory for storing predetermined modifiable information among the information used by said central processing unit for data processing;    an address storage area provided in said flash memory for storing at least the address of the information stored in said information storage area; and    an address-modification control unit for, after at least one of modification of modifiable information stored in said information storage area and addition of modifiable information to said information storage area, and in accordance with said one of the modification of the information and addition of the information, performing one of modification of the address of the information stored in said address storage area and addition of the address of the information to said address storage area,    whereby the information used by said central processing unit for data processing can be freely modified or added.    
     
     
         2 . A data processing device comprising: 
 a read-only memory;    a flash memory capable of modifying information stored therein and adding information thereto;    a central processing unit performing data processing using information stored in said read-only memory and said flash memory;    an information storage area provided in said read-only memory for storing information used by said central processing used for data processing;    an address storage area provided in said flash memory for storing at least the address of predetermined modifiable information among the information stored in said information storage area;    a modified-information storage area provided in said flash memory for storing modified modifiable information; and    an address-modification control unit for, after the modified modifiable information is stored in said modified-information storage area of said flash memory, and in accordance with the modification of the information, modifying the address of the information stored in said address storage area,    whereby the information of said central processing unit used for data processing unit can be freely modified or added.    
     
     
         3 . A data processing device comprising: 
 a read-only memory;    a flash memory capable of modifying information stored therein and adding information thereto;    a central processing unit performing data processing using information stored in said read-only memory and said flash memory;    an information storage area provided in said read-only memory for storing information used by said central processing unit for data processing;    a modified-information storage area provided in said flash memory for storing modified predetermined modifiable information among the information stored in said information storage area; and    an information-modification determining unit for determining whether modified information is stored in said modified-information storage area,    wherein, when said information-modification determining unit determines that the modified information is stored in said modified-information storage area of said flash memory, said central processing unit is arranged to perform data processing in accordance with the modified information stored in said flash memory instead of information stored in said read-only memory.    
     
     
         4 . A method in a data processing device comprising: 
 a read-only memory;    a flash memory capable of modifying information stored therein and adding information thereto;    a central processing unit performing data processing using information stored in said read-only memory and said flash memory;    an information storage area in said flash memory; and    an address storage area in said flash memory;    said method comprising the steps of:    storing in said information storage area predetermined modifiable information among the information used by said central processing unit for data processing;    storing in said address storage area at least the address of the information stored in said information storage area;    performing at least one of modification of modifiable information stored in said information storage area and addition of modifiable information to said information storage area; and    then, in accordance with said one of modification of the information and addition of the information, performing one of modification of the address of the information stored in said address storage area and addition of the address of the information to said address storage area,    whereby the information used by said central processing unit for data processing can be freely modified or added.    
     
     
         5 . A method in a data processing device comprising: 
 a read-only memory;    a flash memory capable of modifying information stored therein and adding information thereto;    a central processing unit performing data processing using information stored in said read-only memory and said flash memory;    an information storage area in said read-only memory;    an address storage area in said flash memory; and    a modified-information storage area in said flash memory;    said method comprising the steps of: 
 storing in said information storage area information used by said central processing unit for data processing;  
 storing in said address storage area at least the address of predetermined modifiable information among the information stored in said information storage area;  
 storing modified modifiable information in said modified-information storage area; and  
 after the modified modifiable information is stored in said modified-information storage area of said flash memory, and in accordance with the modification of the information, modifying the address of the information stored in said address storage area,  
 whereby the information of said central processing unit used for data processing unit can be freely modified or added.  
   
     
     
         6 . A method in a data processing device comprising: 
 a read-only memory;    a flash memory capable of modifying information stored therein and adding information thereto;    a central processing unit performing data processing using information stored in said read-only memory and said flash memory;    an information storage area in said read-only memory; and    a modified-information storage area in said flash memory;    said method comprising the steps of: 
 storing in said information storage area information used by said central processing unit for data processing;  
 storing, in said modified-information storage area, modified predetermined modifiable information among the information stored in said information storage area;  
 determining whether modified information is stored in said modified-information storage area; and  
 when said modified information is stored in said modified-information storage area of said flash memory, performing data processing in said central processing unit in accordance with the modified information stored in said flash memory instead of information stored in said read-only memory.