[sdiy] Does usb c alternative mode allow analog signals on the multi-purpose pins?

[cheater cheater]

Ah, yes, the link was right there, lol

Yeah, these pcb pictures are always a classic in their own right.

On Thu, Nov 17, 2022 at 11:40 PM Chromatest J. Pantsmaker
<chromatest at azburners.org> wrote:
>
> $9 on Amazon.. And it has a "picture" of the circuit board in the images.
>
> On Thu, Nov 17, 2022 at 3:30 PM cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
>>
>> Yep, there are ones with codecs in them. You probably want /an even
>> cheaper one/. Which exact one did you get? How much was it?
>>
>> The cheapest ones might be the passive ones - but who knows. You can
>> find a schematic in appendix A of the doc that Chromatest posted. It's
>> on page 312. The next page has a schematic of that + a charger input
>> port.
>>
>> The page 312 schematic only has the usb c plug / port, the 1/8" jack
>> with a plug-present switch, and wires. That's it. You can build it
>> yourself quite easily either by cutting off a usb c cable, or by
>> getting a usb c breakout pcb.
>>
>>
>> On Thu, Nov 17, 2022 at 11:23 PM Eric Brombaugh via Synth-diy
>> <synth-diy at synth-diy.org> wrote:
>> >
>> > I bought one of those cheap USB C headset adapters as an experiment to
>> > see how well they work.
>> >
>> > https://www.amazon.com/gp/product/B07XYQ2ZKH
>> >
>> > Physically it's tiny - barely larger than the USB and 3.5mm connectors
>> > (plus short cable between them). Tried it out and it worked well, but
>> > then as I dug deeper it turns out that it's *not* passive - it actually
>> > has a full codec + amps inside. Plugging it in enumerates a device on
>> > the bus that's unrelated to my laptop's built-in audio:
>> >
>> > ID 0572:1b09 Conexant Systems (Rockwell), Inc. Hi-Res Audio
>> >
>> > Amazing.
>> >
>> > On 11/17/22 02:31, cheater cheater via Synth-diy wrote:
>> > > If you go to amazon, you'll find nearly infinite USB C to headset
>> > > adapters following this standard, and they're as cheap as 4 euro.
>> > > They'll probably work well, too - even the worst C plugs I've
>> > > encountered on cheap cables are still very resilient. The mini jack on
>> > > the other hand, I mean who knows, but it'll probably take a bunch of
>> > > cycles. The more expensive ones are up to 10 euro, but not more.
>> > >
>> > > On Thu, Nov 17, 2022 at 10:25 AM cheater cheater
>> > > <cheater00social at gmail.com> wrote:
>> > >>
>> > >> Thanks for the pointer to the spec. Appendix A talks about passive
>> > >> audio adapters from USB C to headset TRRS. That includes both input
>> > >> and output analog signals on the pins of a USB C port.
>> > >>
>> > >> Glad that you linked me to the pdf, the last time I tried searching
>> > >> for USB specs I found something completely different and it didn't
>> > >> answer my question.
>> > >>
>> > >> On Tue, Nov 15, 2022 at 9:23 PM Chromatest J. Pantsmaker
>> > >> <chromatest at azburners.org> wrote:
>> > >>>
>> > >>> "NOTE: Adopters may only use the USB Type-C® cable and connector to implement USB or third party functionality as expressly described in this Specification; all other uses are prohibited."
>> > >>> From:
>> > >>> https://www.usb.org/sites/default/files/USB%20Type-C%20Spec%20R2.0%20-%20August%202019.pdf
>> > >>>
>> > >>>
>> > >>> On Tue, Nov 15, 2022 at 11:08 AM cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
>> > >>>>
>> > >>>> As in subject. Is there anything in the spec that speaks against this?
>> > >>>> Where would one go in order to get a definitive answer to this?
>> > >>>> _______________________________________________
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