Firewall Registers; Code Segment Start Address (Fw_Cssa); Code Segment Length (Fw_Csl) - ST STM32L4 5 Series Reference Manual

Firewall (FW)
4.4

Firewall registers

4.4.1

Code segment start address (FW_CSSA)

Address offset: 0x00
Reset value: 0x0000 0000
31 30 29
Res. Res. Res.
15 14 13
Bits 31:24 Reserved, must be kept at reset value.
Bits 23:8 ADD[23:8]: code segment start address
Note: These bits can be written only before enabling the Firewall. Refer to
Bits 7:0 Reserved, must be kept at the reset value.
4.4.2

Code segment length (FW_CSL)

Address offset: 0x04
Reset value: 0x0000 0000
31 30 29
Res. Res. Res. Res.
15 14 13
Bits 31:22 Reserved, must be kept at the reset value.
Bits 21:8 LENG[21:8]: code segment length
The segment area is defined from {ADD[23:8],0x00} to {ADD[23:8]+LENG[21:8], 0x00} - 0x01
Note: If LENG[21:8] = 0 after enabling the Firewall, this segment is not defined, thus not
Bits 7:0 Reserved, must be kept at the reset value.
144/1830
28 27 26 25
Res. Res. Res. Res.
12 11 10 9
ADD[15:8]
rw
The LSB bits of the start address (bit 7:0) are reserved and forced to 0 in order to allow a
256-byte granularity.
Firewall initialization.
28 27 26 25
Res. Res. Res.
12 11 10 9
LENG15:8]
rw
LENG[21:8] selects the size of the code segment expressed in bytes but is a multiple of
256 bytes.
protected by the Firewall.
These bits can only be written before enabling the Firewall. Refer to
Firewall initialization.
24 23 22
Res.
8 7 6
Res. Res.
24 23 22
Res. Res. Res.
8 7 6
Res. Res.
DocID024597 Rev 5
21 20 19 18
ADD[23:16]
rw
5 4 3 2
Res. Res. Res. Res.
Section 4.3.5:
21 20 19 18
LENG[21:16]
rw
5 4 3 2
Res. Res. Res. Res.
Section 4.3.5:
RM0351
17 16
1 0
Res. Res.
17 16
1 0
Res. Res.