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Explains how to use the MSP430 analog-to-digital converter (ADC).

The analog to digital converter (ADC) on the ez430 is a type called a Sigma-Delta (SD) Converter. The way it operates is slightly different from what was described in the previous section (although the end result is the same) but those specifics are out of the scope of this course. The SD converter on the ez430 has 8 channels and a 16 bit resolution. The module is highly configurable and can run largely free of program involvement. In this portion of the lab, we will broadly explain the features of the module, but the particular effects of each register are listed, as usual, in Chapter 12 of the User’s Guide .

Range of measurement

The result of each conversion will be 16 bits long in the form of an unsigned integer whose value is:

SD16_MEMx (65,536) Vin Vrneg Vrpos Vrneg
Where Vin is the input voltage to be measured, Vrneg is the lower reference voltage, and Vrpos is the higher reference voltage. The reference voltages are set to power and ground by default, but they can be changed to an internal reference generator or an externally supplied reference using the SD16CTL register.

Input channels for the adc

The following is a table of the 8 input channels on the ez430. "Analog signal input" channels will take any analog source (we will get to the pin mapping's shortly). Other channels perform specific tool integrated tasks. For example, channel A6 is an integrated temperature sensor. For detailed descriptions of the others, see the User's Guide .

    Sd16 input channels

  • A0 : Analog signal input
  • A1 : Analog signal input
  • A2 : Analog signal input
  • A3 : Analog signal input
  • A4 : Analog signal input
  • A5 : Vcc Vss 11
  • A6 : Integrated temperature sensor
  • A7 : Short for PGA offset measurement
Here is a pin diagram corresponding to the 14 accessible pins showing which pins correspond to which input channels. Notice that each channel has a "+" and a "-" input. Although with other ADC's, we would simply have one input pin and connect the other to the ground, the SD converter requires us to connect the positive and negative inputs to the corresponding input channels. Note that the numbers from 1-14 on the chip correspond to pins 1-14 on the target board.

Pin map

Shows which pins correspond to specific SD converter inputs. Also shows which pins correspond to specific ports (i.e pin 4 is connected to P1.2).

Operation reminders for the adc

Remember the following when attempting to use the ADC:

  • Be sure to enable SD16 interrupts (on SD16CCTL0 ) and to select the specific channel which you are using (on SD16INCTL )
  • After configuring the ADC, you must enable the SD16SC bit to start conversion.
  • All ADC values will be stored in the SD16MEMx variable where "x" is the number of the channel
The User's Guide will be very useful for this lab because of the complexity of this part of the MSP430. Be sure to go over the chapter atleast briefly before jumping into programming.

Questions & Answers

How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
how can I make nanorobot?
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Introduction to the texas instruments ez430. OpenStax CNX. Jun 19, 2006 Download for free at http://cnx.org/content/col10354/1.6
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