EZ-PD™ CCG3 USB Type-C to DisplayPort Cable Solution - Prototype Issues

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NirAlon
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Hi Everyone,

In our design, we've developed a prototype based on the EZ-PD™ CCG3 USB Type-C to DisplayPort Cable Solution reference circuit, with a little change - we've added a USB2.0 data switch. (see attached pic)
The USB switch is routes the DP/DN lines either to the CYPD3120, or to a USB2.0 TYPE-A Connector, upon a manual selection.

The purpose of this change was to test if the CYPD3120 requires connection to the USB DP/DN lines in order to initiate DP altenate mode, or that we can use them for other USB2.0 Peripherals.

The good news is that the board is working, but there is some troubling issues:

1- If we power up the board (By inserting the USB-C Plug to the laptop) when the switch is set to route the USB DP/DN lines to the USB-A connector, there is no signal coming out from the DP port.

Only if the board is powered up when the USB DP/DN lines are routed to the CYPD3120, then the DP becomes active.

Only if we allow the USB lines to be connected first, and then switching them to the USB-A connector, we can accomplish what we intended.

First question - is this situation is normal? can we somehow bypass it? we would like to have full functionality without connecting USB DP/DN lines to the CYPD3120 

2- We use a laptop with a 5V/3A capability, and we noticed that when we try to draw more than 1.5A from VBUS, the laptop is shutting down VBUS. we assume that the CYPD3120 maybe "requesting" the laptop for a lower power level.

Second question - can we re-configure the CYPD3120 firmware in order to make 2.5-3A available?

3- The last issue occurs when we unplug the DP cable (while the board is running OK), and than re-insert the DP cable, the signal does not reappear and after while, there is a pop-up message saying that the USB device is not recognized. in this condition - if we reset the CYPD3120, the display signal comes back to life again.

Third question - can you please try and restore this session on your own board?

Thanks a lot!
Nir

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1 Solution
Pranava_YN
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100 likes received 500 replies posted 250 solutions authored

Hi Nir,

1. DisplayPort Alternate mode mandates presence of a Billboard interface on USB 2.0 lines. CCG3 integrates this USB Billboard device class and therefore it is a must to connect USB 2.0 lines to CCG3. This billboard device may not be used after Alternate mode negotiation, that is the reason it is working when you switch after negotiation.

2. Yes, the requested Sink PDO can easily be modified to fetch 5V/3A.  Please use EZ-PD Configuration Utility to modify this setting in the firmware - https://www.infineon.com/cms/en/design-support/tools/configuration/usb-ez-pd-configuration-utility/ Please refer to User Manual for elaborate explanation of the tool and way to use it.

PranavaYN_0-1645781988797.png

 

3. It would be easier to narrow down this issue with PD analyzer logs. Please let me know if you have any PD Analyzers that sniffs the PD packets? Infineon offers one such PD protocol analyzers - https://www.infineon.com/cms/en/product/evaluation-boards/cy4500/?utm_source=cypress&utm_medium=refe...

Please provide these traces in failure condition so that we can identify the cause.

Best regards,
Pranava

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Pranava_YN
Moderator
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100 likes received 500 replies posted 250 solutions authored

Hi Nir,

1. DisplayPort Alternate mode mandates presence of a Billboard interface on USB 2.0 lines. CCG3 integrates this USB Billboard device class and therefore it is a must to connect USB 2.0 lines to CCG3. This billboard device may not be used after Alternate mode negotiation, that is the reason it is working when you switch after negotiation.

2. Yes, the requested Sink PDO can easily be modified to fetch 5V/3A.  Please use EZ-PD Configuration Utility to modify this setting in the firmware - https://www.infineon.com/cms/en/design-support/tools/configuration/usb-ez-pd-configuration-utility/ Please refer to User Manual for elaborate explanation of the tool and way to use it.

PranavaYN_0-1645781988797.png

 

3. It would be easier to narrow down this issue with PD analyzer logs. Please let me know if you have any PD Analyzers that sniffs the PD packets? Infineon offers one such PD protocol analyzers - https://www.infineon.com/cms/en/product/evaluation-boards/cy4500/?utm_source=cypress&utm_medium=refe...

Please provide these traces in failure condition so that we can identify the cause.

Best regards,
Pranava
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Dear Pranava,

Thanks for your reply!

Regarding question 1 & 2 - Understood.

Question 3 - Attached CSV log file & Toatlphase data center log file that describes the entire procces:

Index 0-182 - Connecting the dongle to the PC

Index 183 - 205 - Connecting DisplayPort cable

Index 206 - 244 - Disconnecting DisplayPort cable

Reinsertion of the DisplayPort cable at this point, did not performed any new CC activity.

You can use totalphase data center in order to load the export file if you wish (CYPD_CCG3_PD_ANALYZE.tdc file)

Thanks for your help!

Nir

 

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NirAlon
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HI,

Can anyone assist with question 3?

Thanks

Nir

 

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Pranava_YN
Moderator
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100 likes received 500 replies posted 250 solutions authored

Hi Nir,

I checked the PD logs you have shared. Can you please check the status of HPD pin when you disconnect and reconnect? Looks like reconnect is not getting detected effectively. Please let me know if you have made any modifications in the source code?

Best regards,
Pranava
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Hi Pranava,
I looked at HPD trace with a scope. upon connection, HPD rises to 3.3V (Clean rise, no over/undershoots or ringing). when disconnecting, HPD goes down to 0V in about 100usec in a smooth discharge. Hardware wise, I cant see anything wrong with HPD.

No modifications where made in the source code.

Do you have a reference dongle that you can try and test this issue at your own setup?

Thanks,

Nir 

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NirAlon
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Hello all,

Still having the same issue when re-attaching the DP cable...

Cypress members - I ask again, can you please support this issue?

Thanks

Nir 

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