The 8051microcontrollers memory is divided into program memory and data memory program memory (ROM) is used for permanent saving program being executed. While data memory (RAM) is used for temporarily storing and keeping intermediate result and variable

Program memory (ROM) is used for permanent saving program (Code) being executed the memory is read only depending on the settings mode in compiler program memory may also used to store a constant variable the 8051 execute program stored in program memory only code memory type specified is used to refer to program memory

8051 memory organization allows external program memory to be added the microcontroller handle external memory depends on the pin EA logical state