usb_power_delivery/thinkpad_yoga_370/README


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-------------------------------------------------------------------------------
USB Power Delivery protocol
-------------------------------------------------------------------------------

This directory contains captures of data communication on the Configuration
Channels of Type-C USB connectors using the USB Power Delivery protocol.

Details:
http://www.usb.org/developers/powerdelivery/


Logic analyzer setup
--------------------

These captures were made using different prototypes of the 'usb-c-grok', which
is an FX2 based device designed to capture USB Configuration Channel traffic.

I made all captures with PulseView, with the samplerate set to 4 MHz, except
when noted otherwise.


Devices used
------------

Lenovo Thinkpad Yoga 370
 - https://psref.lenovo.com/Product/Think_Tablets_and_Convertibles/ThinkPad_Yoga_370
 - 5V source
 - 5/9/12/15/20V sink

Aukey 45W PD source
 - https://www.aukey.com/products/amp-usb-c-wall-charger-with-power-delivery-3-0-pa-y10
 - The only device with Power Delivery 3.0 support
 - 5/9/12/15/20V source
 - Programmable 3 - 16V source

Noname 65W PD source
 - https://www.amazon.de/gp/product/B07538NJDZ/
 - 5/9/12/15/20V source

Cable Deconn USB hub/dock/dongle
 - http://www.cabledeconn.com/sub/?id=708
 - Power Delivery passtrough
 - > supports PR swap
 - USB 3.1 gen 1 hub with Gigabit Ethernet and 2 type A ports
 - USB 2.0 hub with SD card reader and 3.5mm audio interface
 - Displayport switch connected to DP-HDMI and DP-VGA converters
 - Enough magic to make all of the above work at the same time

Anker Powercore+ 26800 PD powerbank
 - https://anker.com/uk/products/variant/powercore-26800-pd/A1375011
 - 26800 mAh, almost 100 Wh
 - 9V sink
 - 5/9/12/15/20V source


thinkpad_yoga_370-anker_powerbank-both_orientations.sr
------------------------------------------------------

I plugged in the powerbank in my laptop with the analyzer in between, then
unplugged, reversed the plug and after around 2 seconds plugged it in again.

At 65 ms we see a CRC packet which the devices have correctly seen but looks
like it didn't capture correctly. At 1986 ms there is some noise, probably
when I was replugging the connector.

The Anker powerbank first advertises only 5V and 15V, then later advertises all
other voltages. I don't know why this happens.


thinkpad_yoga_370_aukey_45w.sr
------------------------------

I plugged the supply in my laptop. I included this because this supply
advertises PPS capability and this is the only PD 3.0 feature in these captures.


thinkpad_yoga_370-passtrough_dongle-anker_powerbank.sr
------------------------------------------------------

First the laptop advertises its capabilities multiple times. Then I plug in the
dongle. At 415 ms the dongle responds and requests 5V from the laptop. Between
460 and 600 ms it does all kinds of stuff that I don't understand. At 606 ms it
enters DisplayPort Alternate Mode. I did not connect a display.

After 3432 ms I plugged in the Anker powerbank to the passtrough port of the
dongle, which sent a Power Role Swap message. Between 3470 and 3570 ms the CC
line is low, because the dongle is switching it's power source. At 3677 ms the
dongle advertises source capabilities to the laptop, which are basically the
powerbanks capabilities reduced by 5W.