Delay the acceptance of PD power contract until some condition is met.

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tegec_3828236
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We are developing a source only device based on the CCG3PA and the CCGx SDK and we have a requirement to perform some external calculations before accepting power contract with devices connected to PD port.

The idea would be after source capabilities are sent to sink, and a request is received, under certain conditions to respond with wait messages until we are ready to resume with power negotiations.

Based on the CCGx SDK I cannot see where one can insert a callback to handle this behaviour into the DPMs normal operation.

Is this possible?

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1 Solution
ShifangZ_26
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10 likes given 250 sign-ins 1000 replies posted

Hi Terry,

1. If it is possible, it is depends on the time your project need to ready the power. As per Power Delivery 3.0 SPEC, the timer define is below:

pastedImage_0.png

If you ready going to do this, you have to customize the firmware after get request from sink and make sure the time out is not met.

2. I also could like to recommend you additional way to easy implement your requirements.

>> 1. You only advertise 5V capabilities on Source Cap.

>> After power negotiation with 5V is settled, you could send GET_SINK_CAP to evaluate SINK's sink capabilities.

>> And then, already the power.

>> Resend the SOURCE_CAP with add new source cap.

Best Regards,

Lisa

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3 Replies
ShifangZ_26
Moderator
Moderator
Moderator
10 likes given 250 sign-ins 1000 replies posted

Hi Terry,

1. If it is possible, it is depends on the time your project need to ready the power. As per Power Delivery 3.0 SPEC, the timer define is below:

pastedImage_0.png

If you ready going to do this, you have to customize the firmware after get request from sink and make sure the time out is not met.

2. I also could like to recommend you additional way to easy implement your requirements.

>> 1. You only advertise 5V capabilities on Source Cap.

>> After power negotiation with 5V is settled, you could send GET_SINK_CAP to evaluate SINK's sink capabilities.

>> And then, already the power.

>> Resend the SOURCE_CAP with add new source cap.

Best Regards,

Lisa

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Thanks for the response, yes I am aware of the alternative way, and I agree that is a good method.

Regarding the first method however,

I am aware that the spec allows for this but am unsure how one would that in the scope of the CCGx API?

For reference I am working with the CYPD3175 and am modifying the CYPD3171-CLA sample project to meet the project needs.

Thanks for all your help!

Regards

TG

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Hi TG,

Currently, the PD stack library is not open API for issue CTRL_MSG_WAIT.

Best Regards,

Lisa

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