expanded view of components

Werner Almesberger werner at openmoko.org
Fri May 15 02:28:34 CEST 2009


Dave Ball wrote:
> I think the components are looking pretty good now,

I'm still not through with the review, but they look quite good, yes.
We still need a bunch of smaller components, but we can make them as
we go.

> What are the things you're thinking we should do differently?

At the circuit level, as described in the fine print on
http://people.openmoko.org/werner/gta02-core/tasks.pdf:

- remove Glamo, NOR, one accelerometer, the audio amp
- connect the LCM to the CPU
- connect the WLAN connector to SPI
  http://svn.openmoko.org/developers/werner/wlan-spi/gta02-spi/rework.pdf

Ah, and I'm also tempted to remove the evil mess that's U4401. Even
if we can put the Calypso on the board, I don't think we want to
use that interface. Almost everything can be done via the regular
modem interface anyway, and for tracing and the like, we could just
put test points within easy reach of the debug connector.

Joerg may have some more audio changes.

At the schematics organization level:

I think we can follow the general structure of Openmoko's GTA02
schematics. One difference is that Openmoko used A3 while we're
probably better off with A4. This means that we'll need more pages.
E.g., CPU power should probably get its own page.

For I/O, I think we should spread things more evenly:

- all that's external USB (49xx) deserves its own page
- I would try to put all the audio things on the same page
- give the rest of the I/O another page

For connecting things to the CPU, it's probably best to follow
Openmoko's example and name most of the nets, instead of trying
to "route" anything but trivial signals in the schematics.

> Getting a decent overall layout now  
> will make life easier later - and hopefully leave us with something that  
> a couple of us can work on in parallel.

Yup. I've now replaced the "expanded" version with the regular
schematics and put the "expanded" one into 
http://svn.openmoko.org/trunk/gta02-core/expanded

- Werner



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