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ADC12CTL0 = REF2_5V | REFON; // Internal 2.5V ref on

Dac12 configuration

The DAC12_0 is configured with 12-bit resolution. The output is updated immediately when a new DAC12 data value is written in straight binary data format to the DAC12_0DAT register.

The full-scale output must be equal to the V REF+ 2.5 V internal reference voltage. Choose a compromise solution between the settling time and current consumption, by selecting a medium frequency and current for both input and output buffers. Configure the following register in order to meet these specifications:

DAC12_0DAT = 0x00; // DAC_0 output 0VDAC12_0CTL = DAC12IR | DAC12AMP_5 | DAC12ENC; // DAC_0 ->P6.6, // DAC_1 ->P6.7, // DAC reference Vref,// 12 bits resolution, // Immediate load,// DAC full scale output, // Medium speed/current,// Straight binary, // Not grouped

Timer_a configuration

Configure Timer_A register to enable an interrupt once every 1 msec. Use the ACLK clock signal as the clock source. This timer is configured in count up mode in order to count until the TAR value reaches the TACCR0 value.

// Before entering in LPM0: TACTL = TACLR | MC_1 | TASSEL_2; // up mode, SMCLK// Timer_A ISR:TAR = 0; // TAR reset TACCR0 = 13600; // Delay to allow Ref to settleTACCTL0 |= CCIE; // Compare-mode interrupt TACTL = TACLR | MC_1 | TASSEL_2; // up mode, SMCLK//*********************************************************// ISR to TACCRO from Timer A //*********************************************************#pragma vector=TIMERA0_VECTOR __interrupt void TimerA0_ISR (void){ DAC12_0DAT++; // Increase DAC's outputif (DAC12_0DAT == 0xfff) DAC12_0DAT = 0; // reset DAC's outputif (flag == 1) // if flag active exite LPM0 {flag = 0; LPM0_EXIT;} }

I/o ports configuration

Port P1 uses the bits P1.0 and P1.2 to activate the ISR whenever the push buttons SW1 and SW2 are activated (low-to-high transition).

// SW1 and SW2 ports configuration P1SEL&= ~0x03; // P1.0 and P1.1 I/O ports P1DIR&= ~0x03; // P1.0 and P1.1 digital inputs P1IFG = 0x00; // clear all interrupts pendingP1IE |= 0x03; // enable port interrupts

DAC12_0 is connected to P6.6. Configure P6 as a special function output:

// P6.6 (DAC12_0 output) // There is no need to configure P6.6 as a// special function output since it was configured in the // DAC12 configuration register (DAC12_0CTL) using// DAC12OPS = 0//********************************************************* // Port1 Interrupt Service Rotine//********************************************************* #pragma vector=PORT1_VECTOR__interrupt void PORT1_ISR (void) {if (P1IFG&0x01) // SW1 generate interrupt DAC12_0DAT += 400; // DAC's output increases if (P1IFG&0x02) // SW2 generate interrupt DAC12_0DAT -= 400; // DAC's output decreases P1IFG = 0x00; // clean all pending interrupts }

Analysis of operation

Observe the analogue signal using an oscilloscope

After compiling the project and starting the debug session, monitor the operation of the application using an oscilloscope probe connected to pin 7 of Header 8 (P6.6).

Measure the current drawn

Assign different values to the bits set in DAC12AMP0. Suspend the execution of the application then directly change the registers. Do not forget that this change requires suspending the operation of the DAC12 by disabling the bit DAC12ENC. Afterwards, this bit must be enabled.

Please note the special cases relating to:

- DAC12 off;

- High impedance output and DAC12 off;

- Output: 0 V.

This example and many others are available on the MSP430 Teaching ROM.

Request this ROM, and our other Teaching Materials here (External Link)

Questions & Answers

what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
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
Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
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
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
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.
Bharti
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
Daniel
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
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
How can I make nanorobot?
Lily
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
NANO
how can I make nanorobot?
Lily
what is fullerene does it is used to make bukky balls
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.
Tarell
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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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