7.4 Peripheral Signal Multiplexing on I/O Lines

SAM9X7 Series devices feature several PIO controllers that multiplex the peripheral set I/O lines.

The Pin Description table defines how the I/O lines are multiplexed on the different PIO controllers.

The column “Reset State” shows whether the PIO line resets in I/O mode or in Peripheral mode. If I/O is shown, the PIO line resets in input with the pull-up enabled, so that the device is maintained in a static state as soon as the reset is released. As a result, the bit corresponding to the PIO line in PIO_PSR (PIO Status register) resets high.

If a signal name is shown in the “Reset State” column, the PIO line is assigned to this function and the corresponding bit in PIO_PSR resets low. That is the case for pins controlling memories, in particular address lines, which require the pin to be driven as soon as the reset is released.