[linux-dvb] Re: Newby, channels.conf, ARM-stuff

[gryn@riffraff.plig.net (Glyn Davies)]

> Benjamin Forgeau writes:
>  > 
>  > 	Thanks for your long answer.
>  > 
>  > > The av711x has an arm core. This has nothing to do with the libdvb api
>  > > since the api is supposed to be hardware independent. The stuff in
>  > > gnufirm is a minimal skeleton for writing an ARM application for the
>  > > AV7110 on a  Siemens/Technotrend/Hauppauge DVB-S board. It does not
>  > > provide any functionality yet. Just as it states in the README file in
>  > > gnufirm.
>  > 
>  > 	As far as I understood, there is an ARM processor inside only because 
>  > the av711x is a chip aimed at the integration of all the components 
>  > needed for a Set-Top Box. The PCI cards use this chip but do not need 
>  > the ARM processor, because we already have our x86. Is that right?
> 
> No, the arm in the av711x drives the mpeg decoder, the section
> filters and of course the communication with the PC. The PC just tells
> the ARM what to do. That is why when your PC crashes sometimes the ARM
> keeps on running and you can still see the last program you selected.
> If you wouldn't have the ARM, you'd have a NOVA card, where the PC
> does all that stuff.
> 
> 

>snip<

I only have a Nova card, so am speculating a bit here really....

As I understand it the difference between a 'full' card and the 'budget' card
is that the 'full' cards have an MPEG2 decoder.  I assume the av711x is such
a beast, and is an MPEG2 decoder, with an ARM in for support.

The philips chip saa7146 ? would therefore link to this chip along with the
DVB demux/whatever - from what I remember on the datasheet that was part of
the design to have those on the same bus?

That would mean you can use the 'full' card as a budget card, or get the ARM
to shovel data through the MPEG2 decoder?

The only other way would be if the ARM was an intermediary between the 7146
and the dvb demux - which would mean you need to download some firmware to
do anything.

I guess I'm asking does the ARM do a piggy in the middle, or is it just there
as an extra?

Cheers,

Glyn


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