SLLSEO6C June 2015 – August 2018 TUSB321
Unattached mode is the primary mode of operation for the TUSB321 device, because a USB port can be unattached for a lengthy period of time. In unattached mode, VDD is available, and all IOs are operational. After the TUSB321 device is powered up, the part enters unattached mode until a successful attach has been determined. Initially, right after power up, the TUSB321 device comes up as an Unattached.SNK. The TUSB321 device checks the PORT pin and operates according to the mode configuration. The TUSB321 device toggles between the UFP and the DFP if configured as a DRP. The PORT pin is only sampled at reset or power up.