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33.7.7
Protecting sectors from being erased/written to
This section describes the procedure to protect sectors from being unintentionally
erased or written to.
■ Activating the write protection by user program
Individual sectors of the flash memory can be protected from being erased or written to by programming
the Flash Memory Write Control registers. For a description of these registers, please refer to 33.4.3 Flash
Memory Write Control registers 0-5 (FMWC0-FMWC5).
■ Activating the write protection without user program interaction
Individual sectors of the flash memory can be protected from being erased or written to by filling in data
into dedicated locations of the Flash memory (Main Flash Write Protection Activation Marker MFWPAM,
Satellite Flash Write Protection Activation Marker SFWPAM and Flash Write Protection Sector Markers
SFWPSM0, MFWPSM0 - MFWPSM4). No user program interaction is needed to activate the write
protection in this case.
After any reset and before user program execution the following is executed:
• When the content of {SFMWPMA1, SFMWPAM0} = 292D3A7BH, then the content of SFWPSM0 is
transferred to FMWC0. For any other value of {SFMWPMA1, SFMWPAM0}, the content of
SFWPSM0 is ignored and the register FMWC0 remains in the initial state.
• When the content of {MFMWPMA1, MFMWPAM0} = 292D3A7BH, then the content of MFWPSM0-
4 is transferred to FMWC1-5. For any other value of {MFMWPMA1, MFMWPAM0}, the content of
MFWPSM1-4 is ignored and the registers FMWC1-5 remain in the initial state.
Figure 33.7-3 Configuration of the Flash Memory Write Protection Activation Marker (MFWPAM0/1,
Address:
DE001C
: SFMWPAM0 (for "Satellite" Flash)
H
DF001E
: SFMWPAM1 (for "Satellite" Flash)
H
DF001C
: MFMWPAM0 (for "Main" Flash)
H
DF001E
: MFMWPAM1 (for "Main" Flash)
H
SFMWPAM0
SFMWPAM1
SFMWPAM0
MFMWPAM1
SFWPAM0/1)
15
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4
CHAPTER 33 FLASH MEMORY
3
2
1
0
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2
1
0
3
2
1
0
3
2
1
0
879
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