ST72F264G ST Microelectronics, ST72F264G Datasheet - Page 16

• Manufacturer Part Number: ST72F264G
• Description: (ST72F260G - ST72F264G) 8-BIT MCU
• Manufacturer: ST Microelectronics

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D a t a S h e e t
ST72260G, ST72262G, ST72264G
FLASH PROGRAM MEMORY (Cont’d)
4.5 Memory Protection
There are two different types of memory protec-
tion: Read Out Protection and Write/Erase Protec-
tion which can be applied individually.
4.5.1 Read out Protection
Read out protection, when selected, makes it im-
possible to extract the memory content from the
microcontroller, thus preventing piracy.
In flash devices, this protection is removed by re-
programming the option. In this case the program
memory is automatically erased and the device
can be reprogrammed.
Read-out protection selection depends on the de-
vice type:
– In Flash devices it is enabled and removed
– In ROM devices it is enabled by mask option
4.5.2 Flash Write/Erase Protection
Write/erase protection, when set, makes it impos-
sible to both overwrite and erase program memo-
ry. Its purpose is to provide advanced security to
applications and prevent any change being made
to the memory content.
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through the FMP_R bit in the option byte.
specified in the Option List.
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Warning: Once set, Write/erase protection can
never be removed. A write-protected flash device
is no longer reprogrammable.
Write/erase protection is enabled through the
FMP_W bit in the option byte.
4.6 Register Description
FLASH CONTROL/STATUS REGISTER (FCSR)
Read /Write
Reset Value: 000 0000 (00h)
1st RASS Key: 0101 0110 (56h)
2nd RASS Key: 1010 1110 (AEh)
Note: This register is reserved for programming
using ICP, IAP or other programming methods. It
controls the XFlash programming and erasing op-
erations. For details on XFlash programming, refer
to the ST7 Flash Programming Reference Manual.
When an EPB or another programming tool is
used (in socket or ICP mode), the RASS keys are
sent automatically.
7
0
0
0
0
0
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OPT
LAT
PGM
0
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