Post- GTA02

[Felipe Balbi]

Hi,

On Wed, 19 Mar 2008 10:27:47 +0000, Andy Green <andy at openmoko.com> wrote:
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> 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.
> 
> S3C2443 is an 130nm incremental improvement over the 2442 in GTA02 with
> 480Mbps USB Device (not OTG) and better clock scaling.  It can accept
> x16 DDR memory.
> 
> S3C6400 is 90nm and has 480Mbps USB2 OTG, 667MHz max clock, some 2D
> acceleration and can accept x32 DDR memory.
> 
>
http://www.samsung.com/global/business/semiconductor/productInfo.do?fmly_id=229&partnum=S3C6400
>
http://www.samsung.com/global/system/business/semiconductor/product/2007/8/21/661267ptb_s3c6400_rev15.pdf
> 
> I like the 6400 better but information is a bit scarce right now and it
> can go either way.

I'd vote for 6400. I think we're a big enough group of people with a big
company supporting us so we can probably push samsung to open some
information.

> 
> 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.

the problem with the micro-usb is space on the case. It'd be cool if we
could make GTA03 (or whatever name) was a thinner.

>  - Discard U-Boot, minimal bootloader direct to kernel

I really like the idea of minimal bootloader, but not direct on the kernel.
LKML won't like it at all. We can have a separate project for this minimal
bootloader. I'm pretty sure 50k lines of code is way enough.

>  - Focus on SD Card rootfs rather than internal memory

This is also a bit weird as if our sd card break we can't use the device
:-s
I like the way it is today allowing the user to choose whether he wants
NAND boot or SD card boot.

>  - 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

Are you taking about the msp430? I really like that chip it's really low
power consumption and really easy to program ;-)
Good catch

> 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.

Again, I really liked the s3c6400, it's already ARM11, operates in 533mhz,
has HS-MMC/SD controller (worth checking if it's sdhci-compliant), it has a
watchdog timer (great success!! :-p), a built-in usb otg transceiver (good
for me, ehehe). Well, it's a really good chip :-), for more info, checkout
[1].

What I'd suggest for the next device (if I can), would be to make it
thinner and put a camera (or maybe two, like most of the phones are now),
s3c6400 already has a camera interface which would really help us and maybe
using a keyboard (qwerty i mean) sliding out from the back of the phone and
accelerometers to get screen rotation; just to exemplify the keyboard
thingy checkout [2[. Before I forget, change the usb connector to micro-AB
receptacle ;-)

[1]
http://www.samsung.com/global/business/semiconductor/productInfo.do?fmly_id=229&partnum=S3C6400
[2] http://www.mobiletechreview.com/phones/HTC-Mogul.htm

I have some thoughts about UI as well.. but this is for another list :-p

-- 
Best Regards,

Felipe Balbi
http://felipebalbi.com
me at felipebalbi.com