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.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).
| LCK0 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCK1 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCK2 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCK3 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCK4 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCK5 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCK6 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCK7 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCK8 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCK9 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCK10 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCK11 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCK12 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCK13 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCK14 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCK15 | Port x lock bit y (y= 0…15) These bits are read/write but can only be written when the LCKK bit is 0. |
| LCKK | Lock key This bit can be read any time. It can only be modified using the lock key write sequence. LOCK key write sequence: WR LCKR[16] = 1 + LCKR[15:0] WR LCKR[16] = 0 + LCKR[15:0] WR LCKR[16] = 1 + LCKR[15:0] RD LCKR RD LCKR[16] = 1 (this read operation is optional but it confirms that the lock is active) Note: During the LOCK key write sequence, the value of LCK[15:0] must not change. Any error in the lock sequence aborts the lock. After the first lock sequence on any bit of the port, any read access on the LCKK bit will return 1 until the next MCU reset or peripheral reset. |