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发表于: 21-04-2018 00:44:57
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Thanks for your feedback.
First I want to say that when CT-2 is developed, there're no much documentation, all we can do is trying to reverse-engineer how it works. Even now, I can only see a little documentation, in some datasheets of chips with HVDCP supported. I guess the HVDCP standard is still not public, your pictures seems directly released from Qualcomm.
As far as I know (Tell me if my statements went wrong), HVDCP hosts should first support DCP, which means that at the initial state, the host should SHORT D+ and D-, this means when you apply a voltage on D+, and if the charger is HVDCP supported, the same voltage should be on D-. Actually I verified this on a lot of chargers, they all have a short on D+ and D- initially. So I guess you didn't get this result on a charger which is not HVDCP supported.
Please tell me if this procedure isn't standard. |
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