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0 pointsilyt2y ago0 comments

> Very very achievable, with minimal effort.

Not with how complicated the whole stack is...

We still can't say "don't charge if other device has no AC power" even tho that info can be propagated via USB-PD...

0 comments

I genuinely don't think it's that complicated. There's a perception about that, but look at the wire protocol for a couple devices & it starts to feel extremely rote extremely quick.

There's a very old very extensive USB HID spec for a ton of battery & charger telemetry things, that for no good reason was never implemented. I'm not sure if USB-PD has overlapping way of sharing data like "is the other side also running on battery?" but we have had the technical possibility of answering that (and how much charge is left what the battery voltage is, but getting low power alarms, more) for literally decades & shame on us for never having implemented it.

ilytOP2y ago

> I genuinely don't think it's that complicated. There's a perception about that, but look at the wire protocol for a couple devices & it starts to feel extremely rote extremely quick.

USB-PD standard is 500+ pages. I remember some early adopters (before ready-made usb-pd controllers were available) complained about that, that the PD code was far bigger than rest of their gadget code. Hell, just look at amount of PD stuff that was subtly or not-so-subtly implemented wrong.

And it's like, they decided to invent their whole own PHY and wire protocol instead of just using CAN or one of the RSXXX ones, for no discernable gain.

Sure it is easier now but not because standard is, but because chip manufacturers made chips specifically to handle that mess...

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