33.5.15.1.1 Physical Freeze

Setting PIO_IOFR.FPHY freezes the following fields (configured in PIO_CFGRx) of the Non-Secure I/O lines if the corresponding MSKx bit is set in PIO_MSKRx:

  • FUNC: I/O Line Function
  • DIR: Direction
  • PUEN: Pull-Up Enable
  • PDEN: Pull-Down Enable
  • OPD: Open Drain
  • SCHMITT: Schmitt Trigger
  • DRVSTR: Drive Strength

For Secure I/O lines, use S_PIO_IOFRx.FPHY and S_PIO_MSKRx to freeze the fields above.

When the physical freeze is currently active on an I/O line, the PCFS flag is set when reading the (S_)PIO_CFGRx of the line.

Only a hardware reset can release the fields listed above.