ZHCSDU0F May 2015 – March 2022 TUSB320
PRODUCTION DATA
Unattached mode is the primary mode of operation for the TUSB320 device, because a USB port can be unattached for a lengthy period of time. In unattached mode, VDD is available, and all IOs and I2C are operational. After the TUSB320 device is powered up, the part enters unattached mode until a successful attach has been determined. Initially, right after power up, the TUSB320 device comes up as an Unattached.SNK. The TUSB320 device checks the PORT pin and operates according to the mode configuration. The TUSB320 device toggles between the UFP and the DFP if configured as a DRP. In unattached mode, I2C can be used to change the mode configuration or port role if the board configuration of the PORT pin is not the desired mode. Writing to the I2C MODE_SELECT register can override the PORT pin only in unattached mode. The PORT pin is only sampled at reset or power up. I2C must be used after reset to change the device mode configuration.