[Gta04-owner] Latest progress
Dr. H. Nikolaus Schaller
hns at goldelico.com
Thu Aug 4 13:58:15 CEST 2011
>> 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?
The TCA is connected to the I2C bus and some test points. The DAC
is not completely connected, i.e. can't be made working.
> And are there any spare connectors/pins on the other side to connect custom
> "add-ons"? (I mean SPI / UART / I2C or similar?)
Yes. There is one I2C available and some other pins.
> Sorry for such dummy questions, I hope I don't steal You too much time :-O
No problem. This list is intended for sharing information.
> Yes, that's clear. I meant rather "what can be wrong with the
> soldering process?"
Well, if we would already know for sure we would have solved
the problem. The issue is that you can't look under the chip
besides by doing Xray. And even then it is not sure that you
can see what is going wrong.
> 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?
I think (but I am not a specialist):
the stencil puts a little too much solder paste on the pads so that
the tin has no chance to (re)flow besides to contact the neighbour...
We can reduce this risk by modifying the PCB/layout for the next
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