GPIO status register can be used to monitor various GPIOs that are configured to achieve desired system behavior. For example to support PD Power Rules with 5 V, 9 V, 15 V and 20 V variable supplies, TPS65987D EVM is designed to use PDO GPIO events that trigger the power supply circuit and generate the desired voltage output. In this case GPIO14, GPIO15, GPIO17 and GPIO20 are assigned with appropriate PDO events to achieve the variable DC-DC supply. Figure 5-1 shows that GPIO14 is driven high indicating PD contract is done for 5 V. Once an explicit PD contract is negotiated for 20 V supply, GPIO20 is driven High by the PD controller as indicated in Figure 5-2.