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From: hiro <23hiro@gmail.com>
To: 9front@9front.org
Subject: Re: [9front] Getting Started with Kernel Development?
Date: Sun, 25 Apr 2021 19:21:30 +0200	[thread overview]
Message-ID: <CAFSF3XNY9Br+eqCNkaqNkF5iXkug2D5TKG2Kj1vVCoYWJ8XPwA@mail.gmail.com> (raw)
In-Reply-To: <CAFSF3XNKTR+hybdf19nAUGqV9Ka7X=FSCBM=qMDwjLbE4A2POw@mail.gmail.com>

sorry, just realized this is rpi3.
rpi3 has no good usb support, maybe that's why they thought gpio will
be more stable?

maybe you'll have to try it out, and if it doesn't work, just upgrade to a rpi4.

On 4/25/21, hiro <23hiro@gmail.com> wrote:
> here's a fitting solution
>
> https://de.aliexpress.com/item/1005002220730177.html
>
> i picked this one because it doesn't have a case,  just like the rpi.
> of course the ones with case are a little cheaper, but this way you
> can say you built it yourself
>
> On 4/25/21, cinap_lenrek@felloff.net <cinap_lenrek@felloff.net> wrote:
>>> I've also got the "BCM2835 ARM Peripherals" spec, which specifies how
>>> to interact with the chip's I2S audio interface.
>>
>> As far as i know, the stock raspberry pi is not using I2S.
>>
>> There are some people that have build their own soundcards
>> for the pi with a I2S DAC but it is not standard.
>>
>> Instead, they hacked together some filter circuit and connected
>> it to a GPIO pin.
>>
>> (This pattern is a logical continuation on raspberry pi hardware
>> design philosphy, where using the existing dedicated peripherals
>> for their intended purpose must be rejected and standards must be
>> ignored: cpu -> GPU, ethernet -> USB, audio -> GPIO, wifi -> SDCARD,
>> usb -> ?????WHATISTHIS????, usbc -> ?????, PXE -> ???????).
>>
>> The GPU has firmware code to drive that GPIO pin and also send
>> audio over HDMI, but todo that you have to talk to the videocore
>> firmware thru a complicated software media streaming interface.
>>
>> Afik, it is possible to drive the gpio pin from the cpu somehow
>> but quality will be garbage and waste alot of power.
>>
>> --
>> cinap
>>
>

  reply	other threads:[~2021-04-25 17:57 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-25 14:15 chötrin.
2021-04-25 16:07 ` cinap_lenrek
2021-04-25 17:20   ` hiro
2021-04-25 17:21     ` hiro [this message]
2021-04-25 23:36     ` Steve Simon
2021-04-26  9:33       ` hiro
2021-04-26 13:01         ` Steve Simon
2021-04-25 22:37   ` chötrin.
2021-04-26 17:08 ` Daniel Morandini
2021-04-26 17:17   ` hiro
2021-04-27  9:39     ` Daniel Morandini
2021-04-27 11:07       ` cinap_lenrek
2021-04-28  8:34         ` Daniel Morandini
2021-04-29  5:10         ` kjn
2021-04-29 11:07           ` Eli Cohen
2021-04-30  1:12             ` chötrin.
2021-04-30  1:24               ` Eli Cohen
2021-04-30  7:36                 ` hiro
2021-04-26 23:40   ` chötrin.

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