The best way to determine if you are connected to a host is by monitoring VBUS. A host must supply VBUS to your peripheral device. Since you are using SIE1 you can connect VBUS on the connector to the OTGVBUS pin. Then by enabling the VBUS interrupt (Device n Interrupt Enable) you can detect when VBUS changes. Our key example of how this is used is when doing OTG functions like in de1. This example can be located at C:\Cypress\USB\OTG-Host\Source\stand-alone\de1 after you install the CY3663 EZ-OTG(TM)/EZ-Host(TM) development kit tools.