9.1.1 Open-Drain Configuration

In addition to the PORTx, LATx and TRISx registers for data control, port pins can also be individually configured for either digital or open-drain output. This is controlled by the Open-Drain Enable for PORTx register, ODCx, associated with each port. Setting any of the bits configures the corresponding pin to act as an open-drain output.

The open-drain feature allows the generation of outputs, other than V_DD, by using external pull-up resistors. The maximum open-drain voltage allowed on any pin is the same as the maximum V_IH specification for that particular pin.