[Gta04-owner] Latest progress

Butrus Damaskus butrus.butrus at gmail.com
Thu Aug 4 13:41:40 CEST 2011


>>> http://download.goldelico.com/gta04/images/IMG_0112.jpg
>>
>> Just curious: what are the parts that are missing on the backside (or
>> is it frontside)?
>
> it is the "frontside" where the display will be. But we still name it the
> bottom layer :)
>
> The spare positions are two B2B connectors (if the board is used
> as a module to sit on a motherboards), a position for a LSM303
> compass/accelerometer. This is not needed since we have a better
> combination of a HMC5883L and a BMA180 (on the other side).
>
> And, there is space for a 8x10 keyboard controller (TCA8418). And
> a VGA DAC. But that one draws too much current and we have not
> found a way to integrate a VGA connector so that it still fits into the
> Freerunner case. Finally, there is room for some U-FL sockets.
>

Are TCA84184 and the DAC's are routed to the B2B connectors then?

And are there any spare connectors/pins on the other side to connect custom
"add-ons"? (I mean SPI / UART / I2C or similar?)

Sorry for such dummy questions, I hope I don't steal You too much time :-O

>>> * a first quick test did show that 3 of them boot to the login: prompt
>>> * 2 of them don't boot
>>> * so we have still some production problem to iron out
>>
>> Do you have some hypothesis what can be wrong?
>
> Either missing contacts or short circuits between BGA balls
> like this one:
>
> http://download.goldelico.com/gta04/images/xr002.jpg
>

Yes, that's clear. I meant rather "what can be wrong with the
soldering process?"
Can the definitions of the reflow process in the datasheets of the
components be wrongly described?
Or are there any problems with the PCB/routing?


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