To enable HPD signaling through PD messaging, a single pin is used as the HPD input and output for each port. When events occur on these pins during a DisplayPort connection though the Type-C connector (configured by firmware), hardware timers trigger and interrupt the digital core to indicate needed PD messaging. When one of the TPS65988's ports is operating as a DP source, its corresponding HPD pin operates as an output (HPD TX), and when a port is operating as a DP sink, its corresponding HPD pin operates as an input (HPD RX). When DisplayPort is not enabled via firmware both HPD1 and HPD2 operate as generic GPIOs (GPIO3 and GPIO4).