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To learn what is involved in Analog to Digital Conversion.

Background questions

  • The ez430 has a 16 bit SD Converter. The number of bits used by the ADC is known as its resolution. What are the number of possible values that the 16 bit SD Converter can represent?
  • Extreme voltages, either too high or too low, cannot be measured correctly. What is the range of analog voltages that can be accurately represented on the ez430? You may want to check the User's Guide or experiment with the hardware.
  • In the real world, signals are polluted by "noise" that alters the quality of the original signal. Signal to Noise Ratio, SNR, is often used as a measure of the quality of a signal. Before a signal is sampled through the ADC, it is helpful to condition the signal in order to improve its SNR. What can be done to condition the signal? Where would it be ideal to condition it and why? (i.e. at the ADC, near the source, at the processor?)
  • The Nyquist Theorem states that a signal must be sampled at least twice as fast as the highest frequency in order to be decoded without error. The minimum sampling frequency is therefore known as the Nyquist Sampling Rate. Typical, audio CDs are sampled at a rate of 44.1 kHz, and can be decoded to 65,536 unique voltage levels. What is the highest frequency that can be represented without error? How many bits per sample are used? What is the total data rate for a stereo CD?

Adc setup

  • Figure out what the following codes is doing. Set up the hardware so that it functions correctly, and comment each line of code. What is the code's function? #include "msp430x20x3.h" void main(void) { WDTCTL |= WDTPW + WDTHOLD; DCOCTL = CALDCO_8MHZ; BCSCTL1 = CALBC1_8MHZ; P1DIR |= 0x01; SD16CTL |= SD16REFON + SD16SSEL_1; SD16INCTL0 |= SD16INCH_6; SD16CCTL0 |= SD16SC; while (1) { while ((SD16IV & SD16IFG)==0); if (SD16MEM6 >= 0xD6D8) P1OUT |= 0x01; else P1OUT &= ~0x01; _NOP(); } }
    Most modern compilers intended for use with embedded processors, such as the IAR Workbench , allow the user to check the status of the registers while the program is halted. This is extremely helpful in debugging code. For example, if the program is halted with a _NOP() after a sample is taken from the ADC, the user may check the SD16MEMx register (by setting a breakpoint at the _NOP() command) to see the new value that has been stored. If a value has changed since the last time the processor was halted, it will turn red in the watch window.
  • Create a version of the program that is completely interrupt driven. The original program uses a while-loop to poll for the interrupt flag. What is the sampling rate? Remember to put the processor into a low power mode and enable interrupts after configuring the SD Converter as discussed in Lab 5

Led dimmer

Add the file containing the LED dimmer function you wrote in Lab 4 to a new project in which you configure the SD Converter. Attach a Photo Diode (DigiKey# ********), a diode that outputs a voltage depending on the ammount of light that hits it, to any one of the SD16 inputs. Input the SD16MEMx value into the LED dimmer function in such a way that the LED's brigtness is indirectly propotional to the ammount of light that hits the Photo Diode. In other words, if we block the light to the diode, the LED should appear brighter; if we shine light on the diode, the LED should appear dimmer. If you do not have access to a Photo Diode, simply set the input to the integrated temperature sensor and perform the same exercise.

Flash storage

Now, chose any analog source (temperature sensor, Photo Diode, function generator etc.) on any input channel and store the values in flash using what you learned in Lab 6 . After a specific number (that you select) of samples are stored, have your program output the values using the printf with the help of a for or while loop. Then take the values and plot them on a graph. You may want to store every 10th (or 20th or 50th etc.) sample in flash to be able to see the analog signal over a longer period of time.

Questions & Answers

how can chip be made from sand
Eke Reply
is this allso about nanoscale material
are nano particles real
Missy Reply
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
where is the latest information on a no technology how can I find it
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
has a lot of application modern world
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
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
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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