Datasheet

40
A/T89C51CC01
4129N–CAN–03/08
Figure 22. Flash and Extra Row Programming Procedure
Hardware Security Byte The following procedure is used to program the Hardware Security Byte space
and is summarized in Figure 23:
• Set FPS and map Hardware byte (FCON = 0x0C)
• Save and disable the interrupts.
• Load DPTR at address 0000h.
• Load Accumulator register with the data to load.
• Execute the MOVX @DPTR, A instruction.
• Launch the programming by writing the data sequence 54h followed by A4h in
FCON register. This step of the procedure must be executed from FM1. The end of
the programming indicated by the FBUSY flag cleared.
The end of the programming indicated by the FBusy flag cleared.
• Restore the interrupts.
Flash Spaces
Programming
Save and Disable IT
EA = 0
Launch Programming
FCON = 5xh
FCON = Axh
End Programming
Restore IT
Column Latches Loading
see Figure 21
FBusy
Cleared?
Clear Mode
FCON = 00h