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Using the MSP-EXP430FG4618 Development Tool and the MSP430FG4618 device implement a voltage ramp generator Basic Timer1.

Laboratory dac: lab1 - voltage ramp generator

Introduction

This laboratory gives an example of the use of the DAC available in the MSP-EXP430FG4618 Development Tool. The DAC module reference is obtained from the ADC module. The DAC is configured with 12 bits resolution in straight binary format. The DAC’s output value is updated every 1 msec by a Timer_A ISR. The buttons SW1 and SW2 are used to manually modify the DAC’s output.

Overview

This laboratory ( Lab1_DAC.c )implements a voltage ramp generator. The DAC module reference is obtained from the ADC module. The DAC is configured with 12-bit resolution, in straight binary format. The output of the DAC value is updated once every 1 msec by an interrupt service routine (ISR) generated by Timer_A. The push buttons SW1 and SW2 are used to manually modify the output of the DAC value. When the microcontroller is not performing any task, it enters low power mode.

Resources

The DAC12_0 module uses V REF+ as reference voltage. It is therefore necessary to activate this reference voltage in the ADC12 module.

The DAC12_0 is connected to Port P6.6 on the Header 8 pin 7. Connect the oscilloscope probe to this port pin.

The output of the DAC is updated whenever Timer_A generates an interrupt. This peripheral is configured to generate an interrupt with a 1 msec time period.

After refreshing the output of the DAC, the system returns to low power mode LPM3.

The push buttons SW1 and SW2 allow the output of the DAC value to be changed manually.

The resources used by the application are:

- Timer_A;

- DAC12;

- I/O ports;

- FLL+;

- Interrupts.

Software application organization

The application starts by stopping the Watchdog Timer.

Then, the ADC12’s reference voltage is activated and set to 2.5 V. A delay is used to allow the reference voltage to settle. During this time period, the device enters low power mode LPM0. The delay period, which is controlled by Timer_A, enables an interrupt when it completes. The interrupt wakes the device and proceeds with the execution of the application.

Timer_A is reconfigured to generate an interrupt once every 1 msec. This interrupt service routine (ISR) updates the output of the DAC.

Ports P1.0 and P1.1 are connected to buttons SW1 and SW2. The ports are configured as inputs with interrupt capability, such that the ISR can decode which button is pushed. If the interrupt source is due to button SW1, then the output of the DAC is increased. If the interrupt source is due to button SW2, then the output of the DAC is decreased.

System configuration

Fll+ configuration

FLL_CTL0 |= DCOPLUS | XCAP18PF; // DCO+ set, // freq = xtal x D x N+1SCFI0 |= FN_4; // x2 DCO freq, // 8MHz nominal DCO SCFQCTL = 121; // (121+1) x 32768 x 2 = 7.99 MHz

Reference voltage selection

The DAC12_0 uses the signal V REF+ as reference voltage. What is the value to write to the configuration register in order to obtain the internally available reference?

Questions & Answers

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
Maciej
Do somebody tell me a best nano engineering book for beginners?
s. Reply
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Devang Reply
are you nano engineer ?
s.
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.
Tarell
what is the actual application of fullerenes nowadays?
Damian
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.
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Mostly, they use nano carbon for electronics and for materials to be strengthened.
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is Bucky paper clear?
CYNTHIA
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
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Do you know which machine is used to that process?
s.
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for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
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Cied
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Sanket Reply
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Damian Reply
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Cied
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abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
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Porter
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Yasmin
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Cesar
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Uday
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AMJAD
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Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
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AMJAD
what is system testing
AMJAD
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Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
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anybody can imagine what will be happen after 100 years from now in nano tech world
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after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
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silver nanoparticles could handle the job?
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I'm interested in Nanotube
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this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
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how did you get the value of 2000N.What calculations are needed to arrive at it
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Source:  OpenStax, Teaching and classroom laboratories based on the “ez430” and "experimenter's board" msp430 microcontroller platforms and code composer essentials. OpenStax CNX. May 19, 2009 Download for free at http://cnx.org/content/col10706/1.3
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