[Arm-netbook] ZeroPhone

[GaCuest]

El 18 de abril de 2017 a las 2:33:42, Luke Kenneth Casson Leighton
(lkcl at lkcl.net) escribió:
> ---
> crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
>
>
> On Mon, Apr 17, 2017 at 7:26 PM, GaCuest wrote:
> > El 17 de abril de 2017 a las 14:30:27, Luke Kenneth Casson Leighton
> > (lkcl at lkcl.net) escribió:
> >> > Why not use the STM32F072 for audio on the laptop?
> >>
> >> not good enough dynamic range and quality, and it is still necessary
> >> to have a amplifier. i tried doing audio on an STM32F103RBT6 - i
> >> learned that it would not be enough. i *almost* managed it though.
> >>
> >
> > Could you use one (poor quality) speaker for the STM32F and when
> > you connect an EOMA68, could you use a CM108AH with one
> > (or two) good speakers?
>
> might be a bit awkward, multiplexing the analog power-pathways (the
> CM108AH drives its outputs @ either 100mA or 500mA) but it's doable.
>
> the other alternatives are:
>
> * to add a proper I2S audio driver IC (from maxim for example).
> however as these typically include a tensilica DSP (tensilica have
> over 1 billion licensed sales of their DSPs, mostly in audio ICs)
> they're typically relatively costly.
>
> * to drive something like a CM108AH directly from the EC. this
> gets... a little hair-raising with the USB paths.
>
> * to find an alternative EC.

Maybe it's easier 3 speakers, a basic speaker directly for the
STM32F (when using only the STM32F) and two good
speakers, connected to the CM108H, when you use the
EOMA68 (in this case the speaker of the STM32F would not work).