TUSB1046A-DCI: TUSB1046A-DCI support DP++ ?

Dennis

Yes, it will support DP++. ) Please note the SNK_CAD pin must be connected to the CONFIG1 pin on DisplayPort receptacle through a buffer like the
SN74AHC1G125. The buffer is required because the internal pulldown on CAD_SNK pin is too strong to register a valid VIH when a Dual mode adapter is plugged into the DisplayPort receptacle. If using TUSB1046 in I2C mode, then system software must disable AUX snooping whenever the CONFIG1
pin is high.

Thanks
David

David,

Thanks for your infomration!

We had connected SNK_CAD pin to the CONFIG1 pin on DisplayPort receptacle, and we maked sure the SNK_CAD is high when HDMI dongle plug in(TUSB1046 in GPIO mode), however the DP++ function still cannot work.

please refer to the following pictures, the DDC_CLK and DDC_Data became strange after Mux. Could you give us some idea? thanks

Attached the waveforms

waveforms.xlsx

Hi, David,

According to Application Report SLLA333, Enabling HDMI over USB Type-C seems to handle the DDC and AUX by a PD controller with SBU mux,
could you help to check TUSB1046A support DP++, Thanks.

Dennis

TUSB1046 supports DP++, please refer to this app note, Figure 6: .

TUSB1046 AUX bus supports DP, it does not support DDC. So AUX snooping is controlled by CAD_SNK. When CAD_SNK is low, which is DP, AUX snoop is enabled. When CAD_SNK is high, which is HDMI, AUX snoop is disabled.

Thanks

David

Hi, David,

Thanks for your answer.

Sorry for that I didn't provide you with more detail information, actually my question is TUSB1046 can support DP++ over Type-c (PD controller is TPS65987)?

Our use case is most likely the figure in attache file, thanks

 DP++.xlsx

Dennis

It supports DP++ over Type C, please refer to my previous attached app note.

Thanks
David

David,

Thanks for your time.

The apnote slla365 seems a application for a design of TUSB1046 to DisplayPort Receptacle. The AUXP/N from DisplayPort receptacle should be routed directly to TUSB1046 and then to
DisplayPort sink through 100 nF AC capacitor. The TUSB1046 SBU1 and SBU2 pins should be left unconnected.

Our design is Type-C Receptacle, the DDC signals will be connected to AUXN/AUXP of TUSB1046, and then output to Type-C Receptacle through SBU1/SBU2;

Now we discovered the DDC signals become abnormal after output from SBU1/SUB2 of TUSB1046. please see attached file.

8831.waveforms.xlsx

Thanks

Dennis

Dennis

TUSB1046 AUX does not support DDC transaction, it is for DP only. DDC needs to be connected directly between Type C receptacle and source.

CAD_SNK needs to be pulled high to disable AUX_SNOOP. AUXn needs to be pulled up and AUXp needs to be pulled down through 100k resistor. SBU1/2 are floating.

Thanks
David

Dennis,

it need an HD3SS215 MUX between GPU and TUSB1046. here is an example about TUSB1046 supporting DP++.

David,

Thanks for your information, becuase TUSB1046A-DCI doesn't support DDC transaction, and based on the example in your previous reply that we need a PD controller which can handle both DDC and AUX to reach DP++ over USB Type-C.

Now our current PD design is TPS65987, does it support DDC and AUX transaction?

Thanks

Dennis

Dennis

TPS5987 only support DP and TBT alternate mode, it does not support HDMI alternate mode.

Thanks
David