[Fwd: Re: gta04 / MPU / JTAG]

joerg joerg.twinklephone at gmx.de
Fri Apr 18 12:33:31 CEST 2008

Am Do  17. April 2008 schrieb Graeme Gregory:
> On Thu, Apr 17, 2008 at 12:18:50PM +0100, Andy Green wrote:
> > | It can be good if we can run the touchscreen from MSP430 ADC.  Maybe see
> > | if you can think that through, we need to use GTA01 style external drive
> > | for X and Y when we measure.  Maybe internal DMA helps there.
> >
> > Forget DMA, AFAICS the A/D is running while cpu sleeping, and we even
> > have a
> > COMPARATOR! :-)) to irq when a certain analog level is detected! That's
> > plain
> > great! Resistive TS no issue at all.
> > OTOH I seen some capacitive TS around those GTA04 modells ?!? Have to ask
> > Allen what's the plan here...
> >
> This is actually a question I meant to bring up and keep forgetting.

There are still multiple options for ts in GTA04. Might become a capacitive 
one. I'm not sure about who does this, but it's still under evaluation.
Meanwhile I study datasheets of some of the C-ts candidates to see which 
interface we have to cope with. Maybe I2C...

Got me a R-ts to hack on it, will tear it apart and do some probes maybe 
tomorrow. This may help to fix jitter issue on GTA02, as well as make for the 
decision for some of the candidates for GTA04.

For the MPU thing: going to create a little example schematics on plumbing 
MSP430 in to a GTA02 based design. Anyway takes some more days to read all 
the datasheets and get used to powerPCB to create a proper design.


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