Re: ice1712 IPGA and ADC controls

[Takashi Iwai <tiwai@suse.de>]

At Tue, 30 Jan 2007 06:18:38 +0000 (UTC),
Tim wrote:
> 
> John Rigg <aldev <at> sound-man.co.uk> writes:
> 
> > If a single volume bar is implemented, does it leave the analog
> > attenuation at zero and adjust the digital attenuation, or does
> > it leave the digital attenuation at zero and adjust the analog
> > attenuation? 
> There is no such thing as analog attenuation on these chips.
> Only an analog gain stage from 0db to +18, followed by a digital 
>  attenuation stage from 0db down to infinity (mute).
> Both of these functions are accessed through the same register,
>  as a continous range from 0 to 164. The first 127 steps
>  'activate' the digital attenuator, with 127 being 0db, while the
>  last 37 steps 'activate' the analog gain.
> In other words, from 0-127 ONLY the digital attenuation stage is
>  activated. From 128 to 164, ONLY the analog gain stage is activated.
> It was intended to be one control.

Exactly.  Thanks for correction.

> Anyways, I say we add some type of 'decorations' to envy24control.
> Some type of markings. Two end-to-end 'braces' along the side spanning the 
>  length of sliders, one labeled "digital att." meaning that the range from 
>  0-127 is digital attenuation, and the other labeled "analog gain" meaning 
>  the range 127-164 is analog gain. It would be a great visual reminder of 
>  this underlying technical detail we have discussed here, so everyone  
>  should understand it.
> And of course all values in db's as well as integers.

Yes.  It's the way to go, IMO.
Make the API simple.  Improve the usability in another part.

A question from usability viewpoint is what is the good way to handle
two linked volumes.  For example,

1) two volume bars can be changed at any time.  If one of them is
   changed, another is automatically set (jumps) to zero.
2) when one volume is set to non-zero, another is visiblly disabled.
   to zero and cannot be changed.  Once after both are set to zero,
   both become accessible.

I think the latter is less confusing, at least.  The jump of volume
bar always annoyed me.

Comments?  Other suggestsion?


Takashi

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