SLVSD02E March 2015 – August 2021 TPS65982
When configured as a DFP, the TPS65982 detects when a cable or a UFP is attached using the C_CC1 and C_CC2 pins. When in a disconnected state, the TPS65982 monitors the voltages on these pins to determine what, if anything, is connected. See the USB Type-C Specification for more information.
|C_CC1||C_CC2||CONNECTION STATE||RESULTING ACTION|
|Open||Open||Nothing attached||Continue monitoring both C_CC pins for attach. Power is not applied to VBUS or VCONN until a UFP connect is detected.|
|Rd||Open||UFP attached||Monitor C_CC1 for detach. Power is applied to VBUS but not to VCONN (C_CC2).|
|Open||Rd||UFP attached||Monitor C_CC2 for detach. Power is applied to VBUS but not to VCONN (C_CC1).|
|Ra||Open||Powered Cable/No UFP attached||Monitor C_CC2 for a UFP attach and C_CC1 for cable detach. Power is not applied to VBUS or VCONN (C_CC1) until a UFP attach is detected.|
|Open||Ra||Powered Cable/No UFP attached||Monitor C_CC1 for a UFP attach and C_CC2 for cable detach. Power is not applied to VBUS or VCONN (C_CC1) until a UFP attach is detected.|
|Ra||Rd||Powered Cable/UFP Attached||Provide power on VBUS and VCONN (C_CC1) then monitor C_CC2 for a UFP detach. C_CC1 is not monitored for a detach.|
|Rd||Ra||Powered Cable/UFP attached||Provide power on VBUS and VCONN (C_CC2) then monitor C_CC1 for a UFP detach. C_CC2 is not monitored for a detach.|
|Rd||Rd||Debug Accessory Mode attached||Sense either C_CC pin for detach.|
|Ra||Ra||Audio Adapter Accessory Mode attached||Sense either C_CC pin for detach.|
When the TPS65982 is configured as a DFP, a current IH_CC is driven out each C_CCn pin and each pin is monitored for different states. When a UFP is attached to the pin, a pulldown resistance of Rd to GND will exist. The current IH_CC is then forced across the resistance Rd generating a voltage at the C_CCn pin.
When configured as a DFP advertising Default USB current sourcing capability, the TPS65982 applies IH_CC_USB to each C_CCn pin. When a UFP with a pulldown resistance Rd is attached, the voltage on the C_CCn pin will pull below VH_CCD_USB. The TPS65982 can also be configured as a DFP to advertise default (500 mA), 1.5 A and 3 A sourcing capabilities.
When the C_CCn pin is connected to an active cable VCONN (power to the active cable), the pulldown resistance will be different (Ra). In this case, the voltage on the C_CCn pin will pull below VH_CCA_USB/1P5/3P0 and the system will recognize the active cable.
The VH_CCD_USB/1P5/3P0 thresholds are monitored to detect a disconnection from each of these cases respectively. When a connection has been recognized and the voltage on the C_CCn pin rises above the VH_CCD_USB/1P5/3P0 threshold, the system will register a disconnection.