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USB EZ-PD Type-C

New Contributor II

CC channel polarity. • CC1 = 0 • CC2 = 1

we are using CC polarity in along with the new Power SDK, and it seems there is an issue with Sleep/Wakeup and or Hanging code

our application is quite simple and has been posted here before with no reply, so here it goes again

CCG3PA 3171 or 3175 used in DFP or UFP application that requires MUX control based on CC line Polarity, seems to work great wth PD core engaged but with type A to C cable that has a pull up to Vbus of 56K (all A to C certified cables have this for legacy support) Code hangs and PlugEvent does not happen (we use plug event to reset HUB ic)

it was completely by accident tht we found out that when first powered up CCG functions correctly and after a while it simply no longer identifies cable direction and plug/unplug event

Here is our video showing Two Led's, that we use as a debug indicating direction of C cable CC line connection (CC1 vs CC2)

Please someone Help as this is delaying our release of our Gen2 8 port power PD hub

1. is it going to sleep and that is why its not working after a while?

2. is it hanging in the code and simply stops responding to new events?

we are not sure

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Moderator
Moderator

Hi Rad,

It is very difficult to debug using LED states. We should first isolate the layer in which this issue is occuring. CC line traces will be very helpful.

Regards,

Rajath

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New Contributor II

This is what a CC trace looks like when connecting a Legacy non PD device (not much data) but lets try to solve the problem that actually exists

image (24).png

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New Contributor II

no-flip-when-this-happens.pngmultiple-plug-events-that-worked-flipping-cable-A-to-C.png

CH0 CC1 on Cypress 3171 CCG3PA / CH1 CC2

Here are Images of it working correctly and than after a minute or so subsequent multiple connections do not provide any CC polarity detection, this is repeatable with WD A to C and Belkin A to C cable (disregard CH3 as this is our reset GPIO driven event)

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New Contributor II

here we have a little more data... this Hard Reset is when A to C cable is used but it only does it on initial attempt of connection and only in one direction

could this be the causehard4.png

for the CC polarity not working?

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New Contributor II

and yes after these hard resets occur subsequent connection of A to C cable will not change CC polarity output (as to identification of cable connection)

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Moderator
Moderator

Hi Rad,

Could you please kindly let me know the firmware revision you are testing? The firmware revision can be got on file ccgx_version.h.

#define FW_BUILD_NUMBER  (1882)

I hope you are using build#1882 for this project.

If you are using Build#1616, you will account this issue. Kindly let me know your comments.

Best Regards,

Lisa

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