Drats! Thanks cory! I'll have to figure out an amplifier for this case.
Dan
On 5/30/07, Cory Sharp <[EMAIL PROTECTED]> wrote:
Yes. See the MSP430 f1611 Data Sheet. On about page 38, "12-bit ADC,
external reference", the minimum positive external reference voltage is
1.4V. - Cory
On 5/30/07, Dan Steingart <[EMAIL PROTECTED]> wrote:
>
> Thanks Cory. Before I go any further, is there a minimum to the
> reference voltage? I'm going for a ceiling of 60 mV.
>
> Dan
>
> On 5/30/07, Cory Sharp <[EMAIL PROTECTED]> wrote:
> >
> > Dan, it sounds like you've done everything necessary. Try bypassing
> > the TinyOS MSP430 ADC components and check the ADC by directly setting the
> > MSP430 control registers. Be sure to appropriately set these registers, in
> > particular:
> >
> > P6SEL
> > P6DIR
> > ADC12CTL0
> > ADC12CTL1
> > ADC12IFG
> > ADC12IE
> >
> > See the MSP430 User's Guide section ADC12 for appropriate values.
> > Then trigger a conversion with
> >
> > ADC12CTL0 |= ENC | ADC12SC;
> > ADC12CTL0 &= ~ADC12SC;
> >
> > You can throw together a quick and dirty ADC interrupt handler like
> > this
> >
> > TOSH_SIGNAL(ADC_VECTOR) {
> > uint16_t iv = ADC12IV;
> > if( iv == 0x06 ) {
> > ADC12IE = 0;
> > reading = ADC12MEM0;
> > post readDone();
> > }
> > }
> >
> > - Cory
> >
> > On 5/30/07, Dan Steingart < [EMAIL PROTECTED]> wrote:
> >
> > > Hello all,
> > >
> > > I've combed the interweb, moved a jumper that was roughly the size
> > > of a grain of sand, and picked through Redfern's brain to the point where
he
> > > said "read the MSP430 manual", but I can't seem to get the external
> > > reference going on my Tmote Sky.
> > >
> > >
> > > things I've done
> > >
> > > - In my ADC header file I changed the VRef to VeRef
> > > - Moved the jumper over
> > > - Fed the ref voltage to ADC0 (port 60, correct?)
> > > - Turned ADC0 into an Input pin with MSP430GeneralIO
> > >
> > > Is there something blatantly wrong here? Is there a contrib file or
> > > other example I'm missing?
> > >
> > > Thanks in advance,
> > >
> > > Dan
> > >
> > >
> > >
> > > _______________________________________________
> > > Tinyos-help mailing list
> > > Tinyos-help@Millennium.Berkeley.EDU
> > > https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
> > >
> > >
> >
> >
>
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