Power Delivery Required in USB4®

Something that has plagued USB-C ports and devices for a while now is USB PD sometimes being included and sometimes not — USB 4 looks to change all that.” As sourced here: https://www.imore.com/usb-4-faq.

Within this Forum we were introduced to some docking stations (hubs, other peripherals or host) not being able to charge adequately (probably around 5V/480mA, which is insufficient, I think, to keep i.MX 8MQ, besides other components, alive for prolonged time) Librem 5 either because of using non-USB3.1 Gen2 Type-C male to USB3.0 Type-A male converter cable, or because of questionable support from inadequate Type-C port that just tries to communicate what expected/needed (charging only, charging+data, DP Alt mode, …) but still not able to function well (have successful handshake) as “usual” source of power, that’s not having out-of-the-box proper function with/to the Librem 5 USB Type-C port.

Therefore this new thread, as I’ve just kind of learned (and therefore having some related questions) that the USB4® cables are USB-IF Certified as well as that the Thunderbolt™ 4 cables are Intel certified and therefore thought that we might focus our future peripherals investments (end-user ones), if any needed at all, around this particular recommendation:

Is it USB4® verified cable (for example with Infineon CYPD2103 chip or Convenient Power E-Marker CPS8821, etc.) going to be filtering out only PD coding/protocol for the Librem 5 Type-C port? Even if “wrong” USB-IF certified PD2.0 or PD3.0 power supply used, filter out only PD 5V/3.0A support (current) as needed, without allowing to the customarily used (randomly found/bought) power supply to constantly send out to Librem 5 strange charging protocols (if so), actually ensure not to communicate toward Librem 5 any of the other charging standards, especially not the QC family (2.0, 3.0, 4+) ones? My question is in accordance, actually/basically related, to this statement: “This 300kHz digital signal is also used to identify that the USB connection can support a USB4 link, so there is no way to implement USB4 without this communication. USB4 ports are not required to supply or receive any power beyond a minimum 5V / 900mA; but they must support PD communication to function as USB4.

I liked certain parts of your post very much, more info for you, like: “Figure 9 shows the PD message format. All PD messages are transmitted at 300KHz +/- 10% over the CC line.”, are (still) here: https://www.embedded.com/usb-type-c-and-power-delivery-101-power-delivery-protocol/.

@amosbatto, sorry, I think now that this article was something that you missed when it was needed (dwc3 − lack of enough amperage either from … or through cable you’ve used to …): “This simplified USB 2.0 Type-C device and host implementation does not support high current charging, active cables, power delivery, analog audio adapter or debug accessories.” Because I, as non-expert, might be wrong as well, what do you think? I think that your L5USA might easily need at least 5V/700mA to start with (by using at least 21AWG power supply wires inside of USB3.0/USB3.1 Gen1 data cable (with either USB-A or USB-C male ends toward source) for certain/particular purpose above 2.0A, counting on 3.0A safe side support from used connecting cable, IMO), to execute what … as you already described.

Every comment is welcomed here as I have nothing to add (as I still do not have single USB4 cable to check for PD charging output, PD only output perhaps?). Thanks!

P.S. In comparison (other words) SHIFT6mq is only happy with the wall power supply or power bank (a source) providing QC3.0 (already avoided on Librem 5 by 100%?) otherwise it don’t want to charge at all (sort of, depends on which main controller, even which cable used). Can Librem 5 use PD protocol only, PD only charge pass-toward itself (as sink) if USB4 cable used? Can someone within this Forum take a look at this, kind of proposal from my side if USB4 certified cable likes to “play with”, even if my question a bit from outer space, a bit of hypothetical color (while like to learn through talking about Librem 5 hardware, its surrounding environment even before practicing/buying any USB4 Type-C cable)?


@Michael24, yes, I’m familiar with this type of extension cable. Example of the longer variant (that will work as requested) is here: https://www.aliexpress.com/item/1005004236152123.html. Another link to the shorter one is here: https://www.aliexpress.com/item/1005004403205227.html.

When the L5USA is turned off, it can charge its battery with 5V x 500mA from the charger. When turned on, it needs more amps to be able to charge the battery, but 5V x 500mA seems to be enough to operate the L5USA–at least the battery charge level doesn’t change and I can use the device.

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Sorry for not being quite clear in my related writing but it was referring to your laptop’s USB 3.1 Type-C port, the one that you used there for the particular purpose (at that time), and to the quality cable needed in terms it can transport enough current. That USB2.0 cable might and probably should be used (on PC/laptop port) because of its well known charging advantage (its charging wires are of the lower AWG number in most cases when compared to the non-charging-compliant USB3.0 cable), as we already learned this, on this Forum from @dos:

And as quite directly related toward USB-C to USB-C cables (including extension cables in particular, extending something that is not compliant, perhaps):

Therefore I was thinking openly, somewhere on this Forum as well, to have battery capacity at above 80% (but not at 100%) before staring with the reflashing process (putting brand new image on the Librem 5 eMMC)? As related: