DocID018909 Rev 11
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RM0090
Embedded Flash memory interface
112
Bits 3:2
BOR_LEV:
BOR reset Level
These bits contain the supply level threshold that activates/releases the reset.
They can be written to program a new BOR level value into Flash memory.
00: BOR Level 3 (VBOR3), brownout threshold level 3
01: BOR Level 2 (VBOR2), brownout threshold level 2
10: BOR Level 1 (VBOR1), brownout threshold level 1
11: BOR off, POR/PDR reset threshold level is applied
Note: For full details on BOR characteristics, refer to the “Electrical
characteristics” section of the product datasheet.
Bits 1:0
0x1: Not used
Option bytes (word, address 0x1FFF C008)
Bit 15
SPRMOD
: Selection of protection mode of nWPRi bits
0: nWPRi bits used for sector i write protection (Default)
1: nWPRi bits used for sector i PCROP protection (Sector)
Bit 14
DB1M
: Dual bank 1 Mbyte Flash memory devices
0: 1 Mbyte single Flash memory (contiguous addresses in bank 1)
1: 1 Mbyte dual bank Flash memory. The Flash memory is organized as two banks
of 512 Kbytes each (see
Table 7: 1 Mbyte Flash memory single bank vs dual bank
organization (STM32F42xxx and STM32F43xxx)
Flash memory organization (STM32F42xxx and STM32F43xxx)
). To perform an
erase operation, the right sector must be programmed (see
for information
on the sector numbering scheme).
Bits 13:12
0x2: not used
nWRP
: Flash memory write protection option bytes for bank 1. Sectors 0 to 11 can be write
protected.
Bits 11:0
nWRPi:
If SPRMOD is reset (default value):
0: Write protection active on sector i.
1: Write protection not active on sector i.
If SPRMOD is set (active):
0: PCROP protection not active on sector i.
1: PCROP protection active on sector i.
Option bytes (word, address 0x1FFE C000)
Bit 15:0
0xFFFF: not used
Table 16. Description of the option bytes
(STM32F42xxx and STM32F43xxx) (continued)