The TUSB546-DCI supports up to 4 DisplayPort lanes at datarates up to 8.1Gbps (HBR3). The TUSB546-DCI, when configured in DisplayPort mode, monitors the native AUX traffic as it traverses between DisplayPort source and DisplayPort sink. For the purposes of reducing power, the TUSB546-DCI manages the number of active DisplayPort lanes based on the content of the AUX transactions. The TUSB546-DCI snoops native AUX writes to DisplayPort sink’s DPCD registers 0x00101 (LANE_COUNT_SET) and 0x00600 (SET_POWER_STATE). TUSB546-DCI disables/enables lanes based on value written to LANE_COUNT_SET. The TUSB546-DCI disables all lanes when SET_POWER_STATE is in the D3. Otherwise active lanes will be based on value of LANE_COUNT_SET.

DisplayPort AUX snooping is enabled by default but can be disabled by changing the AUX_SNOOP_DISABLE register. Once AUX snoop is disabled, management of TUSB546-DCI DisplayPort lanes are controlled through various configuration registers. When TUSB546-DCI is enabled for GPIO mode (I2C_EN = "0"), the CAD_SNK pin can be used to disable AUX snooping. When CAD_SNK pin is high, the AUX snooping functionality is disabled and all four DisplayPort lanes will be active.