When an I/O line is controlled by a peripheral (particularly the Pulse Width Modulation Controller PWM), it can become locked by the action of this peripheral via an input of the PIO Controller. When an I/O line is locked, the write of the corresponding bit in PIO_PER, PIO_PDR, PIO_MDER, PIO_MDDR, PIO_PUDR, PIO_PUER, PIO_ABCDSR1 and PIO_ABCDSR2 is discarded in order to lock its configuration. The user can know at any time which I/O line is locked by reading the PIO Lock Status Register (PIO_LOCKSR). Once an I/O line is locked, the only way to unlock it is to apply a hardware reset to the PIO Controller.