General-purpose I/Os (GPIO)
RM0365
167/1080
DocID025202 Rev 7
10.4.8
GPIO port configuration lock register (GPIOx_LCKR)
(x = A..H)
x= A, B and D in STM32F302xB/C devices, x= A, B, C, D and F in STM32F302x6/8 devices
and x = A, B, C, D, E, F, G, H in STM32F302xD/E devices.
This register is used to lock the configuration of the port bits when a correct write sequence
is applied to bit 16 (LCKK). The value of bits [15:0] is used to lock the configuration of the
GPIO. During the write sequence, the value of LCKR[15:0] must not change. When the
LOCK sequence has been applied on a port bit, the value of this port bit can no longer be
modified until the next MCU reset or peripheral reset.
Note:
A specific write sequence is used to write to the GPIOx_LCKR register. Only word access
(32-bit long) is allowed during this locking sequence.
Each lock bit freezes a specific configuration register (control and alternate function
registers).
Address offset: 0x1C
Reset value: 0x0000 0000
Bits 31:16
BRy:
Port x reset bit y (y = 0..15)
These bits are write-only. A read to these bits returns the value 0x0000.
0: No action on the corresponding ODRx bit
1: Resets the corresponding ODRx bit
Note: If both BSx and BRx are set, BSx has priority.
Bits 15:0
BSy:
Port x set bit y (y= 0..15)
These bits are write-only. A read to these bits returns the value 0x0000.
0: No action on the corresponding ODRx bit
1: Sets the corresponding ODRx bit
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
LCKK
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
LCK15
LCK14
LCK13
LCK12
LCK11
LCK10
LCK9
LCK8
LCK7
LCK6
LCK5
LCK4
LCK3
LCK2
LCK1
LCK0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw