Thank you Cory, your reply explain why pin VeREF connect to ground.
A greeting, Juan Antonio. 2007/5/1, Cory Sharp <[EMAIL PROTECTED]>:
If you read in the MSP430x161x data sheet, in the section "12-bit ADC, external reference", the minimum allowable voltage into VeREF- is 0V. Cheers, Cory On 5/1/07, Oussama Chougna <[EMAIL PROTECTED]> wrote: > > Antonio, > > > > The settings for an ADC port are defined in MSP430ADC12.h header file. > > As the negative reference voltage you can specify VeRef-, but in the > TMote Sky datasheet schematics you can clearly see that the VeRef- pin of > the MSP430 is soldered to ground. > > It is moteiv's design and too bad. > > > > So programming will take no effect on this. > > > > Ground stays zero, so you cannot do conversions between -2,5V and 2,5V. > But you can between 0 and 2,5V. > > > > > > Greeting, > > > > > > oussama > > > ------------------------------ > > *From:* Juan Antonio López Riquelme [mailto:[EMAIL PROTECTED] > > *Sent:* dinsdag 1 mei 2007 13:16 > *To:* Oussama Chougna > *Cc:* yicheng; tinyos-help@millennium.berkeley.edu > *Subject:* Re: [Tinyos-help] can Tmote sky ADC port be used to measure > negativevoltage > > > > Hi Yicheng and Oussama, > > if you read TEP101 (appendix A) then you can know that the conversion > reference is programable. > > > > For use ADC i supose that you use a components in the folder > C:\cygwin\opt\tinyos-2.x\tos\chips\msp430\sensors of template and modify > the fields of struct for use an ADC of expansion port. > > > > You also can change values of fields two (sref) and three (ref2_5v) with > the options that appear below in the same file (C:\cygwin\opt\tinyos- > 2.x\tos\chips\msp430\adc12\Msp430Adc12.h ). > > > > A greeting, > > Juan Antonio. > > > > > > 2007/5/1, Oussama Chougna <[EMAIL PROTECTED] >: > > Hi, > > > > I have this problem too. > > If you check the schematics in the TMote Sky datasheet, you will see > that the negative reference voltage pin is grounded. > > So you can measure only between 0 and any value. > > > > > > oussama > > > ------------------------------ > > *From:* [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > *On Behalf Of *yicheng > *Sent:* woensdag 25 april 2007 20:53 > *To:* tinyos-help@Millennium.Berkeley.EDU > *Subject: *[Tinyos-help] can Tmote sky ADC port be used to measure > negativevoltage > > > > Hi, > > > > Just want to know if negative voltage (like -1.5v) can be measured by > any Tmote sky ADC port? If yes, how can I do it? Do I need to set a negative > reference voltage? > > > > Thanks! > > Yicheng > > > _______________________________________________ > Tinyos-help mailing list > Tinyos-help@Millennium.Berkeley.EDU > https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > > > > > _______________________________________________ > Tinyos-help mailing list > Tinyos-help@Millennium.Berkeley.EDU > https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > >
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