ST STM32F101xx series User Manual

PM0075 Reading/programming the embedded Flash memory
Doc ID 17863 Rev 1 21/31
On every system reset, the option byte loader (OBL) reads the information block and stores
the data into the Option byte register (FLASH_OBR) and the Write protection register
0x1FFF F80C
WRPx: Flash memory write protection option bytes
Bits [31:24]: nWRP3
Bits [23:16]: WRP3 (stored in FLASH_WRPR[31:24])
Bits [15:8]: nWRP2
Bits [7:0]: WRP2 (stored in FLASH_WRPR[23:16])
● For low-density devices, one bit of the user option bytes WRPx is used to
protect 4 pages of 1 Kbyte in main memory block.
– 0: Write protection active
– 1: Write protection not active
In total, one user option byte is used to protect the 32-Kbyte main Flash memory.
WRP0: Write-protects pages 0 to 31
● For medium-density devices, one bit of the user option bytes WRPx is used to
protect 4 pages of 1 Kbyte in main memory block.
– 0: Write protection active
– 1: Write protection not active
In total, four user option bytes are used to protect the 128-Kbyte main Flash
memory.
WRP0: Write-protects pages 0 to 31
WRP1: Write-protects pages 32 to 63
WRP2: Write-protects pages 64 to 95
WRP3: Write-protects pages 96 to 127
● For high-density devices, one bit of the user option bytes WRPx is used to
protect 2 pages of 2 Kbytes in main memory block. However, the bit 7 of
WRP3 write protects pages 62 to 255.
– 0: Write protection active
– 1: Write protection not active
In total, four user option bytes are used to protect the 512-Kbyte main Flash
memory.
WRP0: Write-protects pages 0 to 15.
WRP1: Write-protects pages 16 to 31.
WRP2: Write-protects pages 32 to 47.
WRP3: bits 0-6 write-protect pages 48 to 61
bit 7 write-protects pages 62 to 255.
● For connectivity line devices, one bit of the user option bytes WRPx is used to
protect 2 pages of 2 Kbytes in main memory block. However, the bit 7 of
WRP3 write-protects pages 62 to 127.
– 0: Write protection active
– 1: Write protection not active
In total, four user option bytes are used to protect the 256-Kbyte main Flash
memory.
WRP0: Write-protects pages 0 to 15.
WRP1: Write-protects pages 16 to 31.
WRP2: Write-protects pages 32 to 47.
WRP3: bits 0-6 write-protect pages 48 to 61
bit 7 write-protects pages 62 to 127.
Table 8. Description of the option bytes (continued)
Flash memory
address
Option bytes

ST STM32F101xx series Specifications

General

Brand	ST
Model	STM32F101xx series
Category	Controller
Language	English