[Open-graphics] Apple TV

[James Richard Tyrer]

Timothy Normand Miller wrote:
> So, in other words, a very powerful MythTV/Tivo sort of device? Would
>  it have a hard drive?

Actually, that wasn't what I had in mind.  A computer has a hard drive,
so I don't see the need for another one in the box.

> One of my friends spent months researching MythTV with the intention
>  of building one.  He ultimately came to the conclusion that getting
> a Tivo would be less expensive, more reliable, require less effort to
>  set up, less effort to maintain, and there would be someone to 
> complain to when something went wrong.  We could take a step towards
>  correcting this problem by developing a "supported platform," where
> a company, such as Traversal, would sell it and take responsibility
> for the customer service.
> 
> What would be good to see is a full spec, inside and out.

If I was having the chip or chips made, I would have a CPU with needed
peripherals (USB & Ethernet), a VGA core and digital video outputs
(serial and RGB) and the audio & video decode and scaling chip with
digital RGB output and digital audio output (parallel & SPDIF). The
memory controller needs to be in here somewhere -- if multiple chips, I
would go with the AV chip since it needs the fastest access to memory.
If we must have component output it would also need a RGB to component
converter (I presume that this could be analog).  And you need a Video
and Audio DAC.

Trying to make this with existing chips is going to require research.
As odd as this seems, many of the existing chips have too many features
(e.g. do you want two chips with memory controllers, and video
outputs?).  That is, it appears that chips are available that have the
needed features but they seem to have too many of them.

> Include software requirements in the spec, even if the existing 
> software, like MythTV, doesn't already have the features you require.
>  When you have made all of the appropriate engineering compromises, 
> you'll be able to go straight to specing out the components that 
> would go into it.

I don't see the need for much software for this since this would just
appear to the system as another X11 screen.  So, all you really need is
an X11 driver.  If you need more control of the device through I/O
control, you would need either a command line or a GUI user space
interface to the driver.
> 
> BTW, don't try too hard to make the thing tiny.

I wouldn't try too hard, but small size is a feature Apple is pushing.
OTOH, the Dolby digital & DTS I bought used (Technics) is huge and,
therefore, very impressive.

> We're going to want an array of things like USB ports and even a
> serial port for both general I/O and as access to the inner workings
> when we're debugging the thing.

The Apple TV had Ethernet and USB.  You can always take the lid off to
connect a serial bus monitor.

> Don't spec something without having designed in a way to test it. 
> Otherwise, a "simpler" design could take far longer to get to market.
> 
> 
Yes, any new design needs to be able to read the boundary scan from the
chips.

-- 
JRT

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