Saturday, February 27, 2016

8051 Program Memory

8051 Program or Code Memory

  • 8051 has 4K bytes of internal program memory.
  • It is allowed to add 60K bytes of external program memory in addition to internal memory.
  • Up to 64K bytes of program memory.
  • It may be on-chip or off-chip or combination of both.
  • It can be ROM or EPROM.
  • Some variants use on-chip flash memory and allow in-system or in-application re-programming.
  • It is possible to store read-only data in program memory using special function register and MOVC instruction.
8051 Program Memory

  • 8051 starts executing program instructions from address 0000H in the program memory.
  • EA pin should be connected to Vcc to fetch instructions from internal memory initially.
  • Control will automatically move to external memory to fetch instruction from them.
  • EA pin should be connected to ground to fetch instruction from external memory only.
  • Internal program memory can be locked and protected.

Related topics:
8051 Data Memory   |   8051 Register Bank   |   8051 Bit Memory   |   8051 Special Function Registers   |   8051 Memory Map

List of topics: 8051

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