03-10-2012, 11:50 AM
MEMORY ORGANIZATION of 8051
MEMORY ORGANIZATION of 8051.ppt (Size: 780.5 KB / Downloads: 284)
Internal Memory
A functioning computer must have memory for program code bytes, commonly in ROM, and RAM memory for variable data that can be altered as the program runs
8051 has internal RAM (128 bytes) and ROM (4Kbytes)
8051 uses the same address but in different memories for code and data
Internal circuitry access the correct memory based on the nature of the operation in progress
Can add memory externally if needed
Internal ROM
Internal ROM occupies the code address space from 0000H to 0FFFH (Size = 4K byte)
Program addresses higher than 0FFFH will automatically fetch code bytes from external program memory
Code bytes can also be fetched exclusively from an external memory by connecting the external access pin (EA) to ground