TUSB1064: Pin Assignment E

Eugene

Intellectual 320 points

Part Number: TUSB1064

Tool/software:

I'm trying to support Pin Assignment E by GPIO control on my custom board.

The DP sink device which I use can swap lanes and invert the polarity of ML and AUX.

My custom board is similar to the Figure 28 on the datasheet, but I don't connect SBU lines to PD controller.

I tested but I couldn't display the signal with Pin Assignment E in this case.

But after I changed SBU connection like the Figure 29, I could display the signal with Pin Assignment E.

I prefer to use Figure 28 circuit because I'd like to reduce ICs.

Question

How can I display the signal with Figure 28 connection? Why PD controller is connected to SBU lines?

7 months ago

0 Vishesh Pithadiya 7 months ago

TI__Mastermind 39880 points

Hi Eugene,

The PD needs the AUX information as the PD controller is in charge or configuring the DP alt mode itself. This means lane count, datarate, etc.. You will need to connect the PD controller to snoop the AUX/SBU lines to make figure 28 configuration to work.

0 Eugene 7 months ago in reply to Vishesh Pithadiya

Intellectual 320 points

Thank you for your help.

I'd like to snoop the AUX lines but there was no link training signal on AUX line in figure 28 case even if I swapped AUX of DP sink.
I checked the waveform of SBU1/2 pins and AUXp/n pins after DP source is connected.
The result is there is Link Training signal on SBU1/2 pins but there are no signal on AUXp/n pins.
I think EN, Flip and CTL0/1 pins were properly set because I can display image in figure 29 case.

Do you know why the AUX signal cannot pass through TUSB1046 if I use the SBU pins(24pin and 25pin) and the AUX MUX inside the TUSB1064.

0 Vishesh Pithadiya 6 months ago in reply to Eugene

TI__Mastermind 39880 points

Hi Eugene,

Sorry for the delays, I was out on travel. Are you able to share the schematic.

Are you in I2C mode or GPIO mode?

0 Eugene 6 months ago in reply to Vishesh Pithadiya

Intellectual 320 points

Hi Vishesh

The schematic is almost same as TUSB1046 EVM.

The differences are the following.

1. R12 and R13 are implemented.

2. EN of TUSB1046 is controlled by the plug event from the PD controller.

3. P3 connector is replaced to DP sink device.

4. I2C_EN of TUSB1046 is pulled down.

I'm using in GPIO mode, so I don't need to disable AUX snoop feature.

But there is no link training signal on AUXn and AUXp lines when the PD negotiation result was in Pin Assignment E.

TUSB1064EVM_HSDC025A-002 Schematics_add_comment.pdf

0 Vishesh Pithadiya 6 months ago in reply to Eugene

TI__Mastermind 39880 points

Hi Eugene,

Thanks for the additional information.

Please depopulate R12 and R13.

Can you confirm the jumper settings for CTL0 and CTL1?

0 Eugene 6 months ago in reply to Vishesh Pithadiya

Intellectual 320 points

Hi Vishesh

Thank you for your help.

I removed R12 and R13 but the result was same. There are no signal on AUXp/AUXn lines even if there are some pules on SUB1/2 lines.

I checked CTL0/1 in this situation and the result was CTL1 = High and CTL0 = Low.

In addition, EN was High and I2C_EN was Low.

0 Vishesh Pithadiya 6 months ago in reply to Eugene

TI__Mastermind 39880 points

Have you already tried the flip orientation of the type-C cable?

0 Vishesh Pithadiya 6 months ago in reply to Vishesh Pithadiya

TI__Mastermind 39880 points

Can you send a full block diagram of the path from the type C source to the DP sink?

0 Vishesh Pithadiya 6 months ago in reply to Vishesh Pithadiya

TI__Mastermind 39880 points

Additionally repopulate R12 and R13. Can you measure the common mode of the AUX channel? It should be that AUXp is 3V and AUXn is .3V

0 Vishesh Pithadiya 6 months ago in reply to Vishesh Pithadiya

TI__Mastermind 39880 points

Is the DisplayPort sink able to perform main link and AUX inversion? If not you may need to use the following implementation:

0 Vishesh Pithadiya 6 months ago in reply to Vishesh Pithadiya

TI__Mastermind 39880 points

Hi,

I'm closing this thread due to inactivity

0 Eugene 6 months ago in reply to Vishesh Pithadiya

Intellectual 320 points

Sorry for late.

I didn't have time to prepare the full block diagram. But the differences between my custom board and TUSB1064EVM are following.

Eugene said:
1. R12 and R13 are implemented.

2. EN of TUSB1046 is controlled by the plug event from the PD controller.

3. P3 connector is replaced to DP sink device.

4. I2C_EN of TUSB1046 is pulled down.

Vishesh Pithadiya said:
Have you already tried the flip orientation of the type-C cable?

Yes, the result was same no display. The flip pin was High when the cable was inverted.

Vishesh Pithadiya said:
Additionally repopulate R12 and R13. Can you measure the common mode of the AUX channel? It should be that AUXp is 3V and AUXn is .3V

Yes.

Vishesh Pithadiya said:
Is the DisplayPort sink able to perform main link and AUX inversion? If not you may need to use the following implementation:

Yes, the DP sink is able to perform main link and AUX inversion.

0 Vishesh Pithadiya 6 months ago in reply to Eugene

TI__Mastermind 39880 points

Hi Eugene,

Just want to confirm, because I've noticed you mention TUSB1046 and TSUB1064. which part is the one you are using?

Additionally, please share your full schematic. and layout. It will be easier for me to help debug with this information.

Additionally, please share a block diagram of the system when you get the chance.

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TUSB1064: Pin Assignment E