Datasheet

CHAPTER 16 FLASH MEMORY
User’s Manual U18172EJ3V0UD
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(7) Flash write buffer register (FLW)
This register is used to store the data to be written to the flash memory.
This register is set with an 8-bit memory manipulation instruction.
Reset signal generation clears these registers to 00H.
Figure 16-16. Format of Flash Write Buffer Register (FLW)
Address: FFA8H After reset: 00H R/W
Symbol 7 6 5 4 3 2 1 0
FLW FLW7 FLW6 FLW5 FLW4 FLW3 FLW2 FLW1 FLW0
(8) Protect byte
This protect byte is used to specify the area that is to be protected from writing or erasing. The specified area
is valid only in the self-programming mode. Because self-programming of the protected area is invalid, the data
written to the protected area is guaranteed.
Figure 16-17. Format of Protect Byte (1/2)
Address: 0081H
7 6 5 4 3 2 1 0
1 PRSELF4 PRSELF3 PRSELF2 PRSELF1 PRSELF0 1 1
•
μ PD78F9200, 78F9500
PRSELF4 PRSELF3 PRSELF2 PRSELF1 PRSELF0 Status
0 1 1 1 0 Blocks 3 to 0 are protected.
0 1 1 1 1
Blocks 1 and 0 are protected.
Blocks 2 and 3 can be written or erased.
1 1 1 1 1 All blocks can be written or erased.
Other than above Setting prohibited
•
μ PD78F9201, 78F9501
PRSELF4 PRSELF3 PRSELF2 PRSELF1 PRSELF0 Status
0 1 1 0 0 Blocks 7 to 0 are protected.
0 1 1 0 1
Blocks 5 to 0 are protected.
Blocks 6 and 7 can be written or erased.
0 1 1 1 0
Blocks 3 to 0 are protected.
Blocks 4 to 7 can be written or erased.
0 1 1 1 1
Blocks 1 and 0 are protected.
Blocks 2 to 7 can be written or erased.
1 1 1 1 1 All blocks can be written or erased.
Other than above Setting prohibited