Post- GTA02

joerg joerg.twinklephone at gmx.de
Wed Mar 19 13:20:29 CET 2008


Am Mi  19. März 2008 schrieb Andy Green:
> - gpg control packet
> Hi folks -
> 
> We had some internal talk about how to go post GTA02 and Wolfgang wants
> us to make it external.
> 
> We have a choice about basing on S3C2443 or S3C6400.  A lot of the info
> is confidential but not these high level things which are public domain
> on Samsung's site.

On Samsung's site I see a registration form to get access to user-manual etc.
So if everybody may register to get this "confidential" data which is 
essential for writing drivers for the video accel / camera / ..., we had a 
lot less of these NDA problems. This is a point to be clearly checked and 
contracted upon with Samsung, prior to decision for their device.


> S3C6400 is 90nm and has 480Mbps USB2 OTG, 667MHz max clock, some 2D
> acceleration 

plus H263/H264 coding and decoding and LCD-interface. This means we get rid of 
glamo, no?


> 
> Some other concepts kicked around:
> 
>  - Merge the debug board function on to the phone, perhaps with internal
> micro USB used for debricking and hacking.  No write-once memory.
> 
>  - Discard U-Boot, minimal bootloader direct to kernel
> 
>  - Focus on SD Card rootfs rather than internal memory

As long as we get a second media slot, preferably one that's accessable from 
outside, 'hotswap', that's not adding to the footprint of the case as e.g a 
USB-stick does.


> 
>  - Add a small lowpower MPU like TI MPS430 to manage everything
> seamlessly when main CPU is down.  Stuff like motion sensors, wake
> sources, battery management, maybe touchscreen, leds so there is an
> always-on "guiding hand" in the phone that is consistent and reliable

Well sure a useful gadget, but hard to interface with the main cpu in a way 
that's not a bottleneck. Should G-meters be accessed by main cpu via this 
MPU, or shall there be concurrent access. The first sacrifices flexibility 
(If MPU can't do it, it can't be done), the second adds complexity to both hw 
& sw.
I'd prefer to have a main CPU, that's up to reasonable power and back to 
suspend in a few milliseconds, plus a nice timer to periodically wake the 
CPU, and all needed interupt lines well done, and intelligent peripherials.
Alas i fear that's not easy to design.

> 
> To be clear though -- GTA02 is soon going to actually exist, and this is
> just future talk right now.  But because of that, if you have any ideas
> about future arch, now is the time to throw them in and they will at
> least get the time of day.

Open up existing bonus functions like camera IF, video out..., don't spoil 
them by using 3 of the 15 GPIOs for other tasks, but instead route them to 
free pins of some (debug?) connector, or testpoints at least.

cheers
jOERG




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