[ANN]: GTA04 (Beagleboard inspired Openmoko Upgrade) - Early Adpoter Program

[Dr. H. Nikolaus Schaller]

Hi Sam,

Am 22.12.2010 um 01:54 schrieb sam tygier:

> On 21/12/10 15:33, Dr. H. Nikolaus Schaller wrote:
>> Please note that it does *not* include the LCD module, case and
>> battery, because it is a motherboard-replacement to existing
>> Openmoko units (Freerunner and Neo1973).
> 
> how much work is it to do this motherboard replacement? do we just unscrew our old openmoko, and put it in? does it need soldering? would it be reversible?

Yes - it is reversible.

It is essentially the following steps:

* remove battery, SIM, SD
* open the Openmoko (screws)
* remove the motherboard
* unplug the GPS antenna
* remove the Display (this is quite tricky without breaking the module or ripping off the cables)
* glue to the GTA04 motherboard
* scratch a little to widen the USB connector hole (the GTA02 has a Mini-B socket, the GTA04 a full OTG which is slightly wider)
* install the GTA04 board
* plug in the GPS antenna
* close the Openmoko
* install (different) SD card, SIM card, battery

We plan to make a video of this process.

If you don't want to tackle with the display I recommend to add a new display module for
the new board.

> 
> Also what has been done to improve sound quality?

Sound is handled by completely different components.

The main audio codec is within the TPS65950. The interface
to the UMTS module is PCM (digital). So the only deterioration
of sound quality is between the microphone and the TPS.

We have ordered a sample of a digital microphone chip. So we may
replace the analog path at all and make it more robust.

On the speaker power amplifier the TPS design has much bigger
coupling capacitors than the GTA02 had. So the "bass-fix" is
already designed in.

Nikolaus