at89c51re2-slsem ATMEL Corporation, at89c51re2-slsem Datasheet - Page 43

• Manufacturer Part Number: at89c51re2-slsem
• Description: At89c51re2 8-bit Flash Microcontroller
• Manufacturer: ATMEL Corporation

Extra Row
Hardware Security Byte (HSB)
7663B–8051–03/07
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The following procedure is used to program the Extra Row space and is summarized in
Figure 5:
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Figure 5. Flash and Extra row Programming Procedure
The following procedure is used to program the Hardware
and is summarized in Figure 6:
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Enable the interrupts.
Load data in the column latches from address FF80h to FFFFh.
Disable the interrupts.
Launch the programming by writing the data sequence 51h followed by A1h in
FCON register.
The end of the programming indicated by the FBUSY flag cleared.
Enable the interrupts.
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.
Column Latches Loading
Launch Programming
End Programming
Save & Disable IT
Programming
see Figure 4
FCON = 00h
FCON= 50h
FCON= A0h
Clear Mode
Cleared?
Restore IT
FBusy
Flash
EA= 0
Column Latches Loading
Launch Programming
End Programming
Save & Disable IT
Programming
see Figure 4
FCON = 00h
FCON= A1h
Clear Mode
FCON= 51h
Cleared?
Restore IT
XROW
FBusy
EA= 0
Security
Byte space
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