Saturday, February 27, 2016

8051 Program Counter

Program Counter (PC)

8051 Program Counter

  • The only register that is not memory mapped in 8051.
  • Size: 16-bit.
  • Always points to the address of the next instruction to be executed.
  • After execution of one instruction PC is incremented to point to the address of the next instruction to be executed.
  • PC will increase automatically.
  • The content of PC will be placed on the address bus to find and fetch the desired instruction.
  • User cannot write in PC.
  • Since PC is 16-bit 8051 can access program address from 0x0000 to 0xFFFF, up to 64K bytes.
  • After reset, PC always points to 0x0000 of program memory and is incremented each time an instruction is executed.
  • The first instruction must be placed at 0x0000 of Program memory.



Related topics:
8051 Registers   |   8051 R Registers   |   8051 SFR   |   8051 P Registers   |   8051 Stack   |   8051 Stack Pointer   |   8051 Data Pointer   |   8051 PCON Register   |   8051 TCON Register   |   8051 TMOD Register   |   8051 Timer Registers   |   8051 SCON Register   |   8051 SBUF Register   |   8051 IE Register   |   8051 IP Register   |   8051 PSW Register   |   8051 A Register   |   8051 B Register

List of topics: 8051

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