21.5.1.2 Programming I/O Line Configuration

The user must first define which I/O line in the group will be targeted by writing a 1 to the corresponding bit in the PIO Mask Register (PIO_MSKRx). Several I/O lines in an I/O group can be configured at the same time by setting the corresponding bits in PIO_MSKRx. Then, writing the PIO Configuration Register (PIO_CFGRx) apply the configuration to the I/O line(s) defined in PIO_MSKRx. All the I/O lines defined as Privileged-Access mode in the PIO_P_SIO_PARx must be configured by writing the PIO_P_CFGRx and PIO_P_MSKRx registers.

For more details concerning the I/O line configuration using PIO_MSKRx and PIO_CFGRx, see section I/O Lines Programming Example.