SLVSDC2C February 2016 – August 2021 TPS65981
PRODUCTION DATA
When configured as a DFP, the TPS65981 detects when a cable or a UFP is attached using the C_CC1 and C_CC2 pins. When in a disconnected state, the TPS65981 monitors the voltages on these pins to determine what, if anything, is connected. See the USB Type-C Specification for more information.
Table 9-1 shows the high-level detection results. Refer to 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 TPS65981 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 pull-down 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 TPS65981 applies IH_CC_USB to each C_CCn pin. When a UFP with a pull-down resistance RD is attached, the voltage on the C_CCn pin will pull below VH_CCD_USB. The TPS65981 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 pull-down 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.