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Receiving data

To read data from the DSP, a read channel must be set up. This is done using the invoke open command with an 'R' parameter. invoke(h,'Open','ochan','R'); Reading data from the DSP board is a little more complicated. It seems that the DSP board buffers all the data. To get the latest piece of data, you must first 'Seek' to the current message. [status,nummsgs] = invoke(h,'GetNumMsgs');status = invoke(h,'Seek',nummsgs); Once at the correct message, the actual reading can be done. [status, values] = invoke(h,'ReadI2'); As with writing, the port should be closed after reading.

Using matlab gui features

MATLAB has some nice Graphical User Interface (GUI) features which can be used to control the flow of data to and from the RTDX port. The basic implementation consists of a blank window (figure) which can have differentinterface elements placed on it. These elements can be sliders, buttons, text boxes, etc...

When an element is accessed (for instance, a slider is moved, or a button is pushed), MATLAB will execute a "callback routine" which is a MATLAB function defined by the user. Desgining these interfacesis simple.

Creating a user interface with sliders

1 % rtdx_sliders - initializes RTDX port and sets up three sliders 23 h = actxserver('RTDX'); 45 % open a blank figure for the slider 6 Fig = figure(1);7 % open sliders 8 % first slider9 sld1 = uicontrol(Fig,'units','normal','pos',[.2,.7,.5,.05],...10 'style','slider','value',4,'max',254,'min',0,'callback','rtdx_wrt_sliders'); 1112 % second slider 13 sld2 = uicontrol(Fig,'units','normal','pos',[.2,.5,.5,.05],... 14 'style','slider','value',4,'max',254,'min',0,'callback','rtdx_wrt_sliders');15 16 % third slider17 sld3 = uicontrol(Fig,'units','normal','pos',[.2,.3,.5,.05],...18 'style','slider','value',4,'max',254,'min',0,'callback','rtdx_wrt_sliders');
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Lines 9 through the end create the three sliders for the user interface. Several parameters are used to specify the behavior of each slider. The first parameter,Fig, tells the slider to create itself in the window we created in Line 6. The rest of the parameters are property/value pairs:

  • units : Normal tells Matlab to use positioning relative to the window boundaries.
  • pos : Tells Matlab where to place the control.
  • style : Tells Matlab what type of control to place. slider creates a slider control.
  • value : Tells Matlab the default value for the control.
  • max : Tells Matlab the maximum value for the control.
  • min : Tells Matlab the maximum value for the control.
  • callback : Tells Matlab what script to call when the control is manipulated. rtdx_wrt_sliders is a Matlab file that writes the values of the controls to the RTDX port.
Every time a slider is moved, the rtdx_wrt_sliders.m file is called:

1 % rtdx_wrt_sliders : writes values of sliders out to rtdx 23 % open rtdx port for data transfer 4 status = invoke(h,'Open','ichan','W');5 6 % send valuefrom sld1 7 v1 = round(get(sld1,'value'));8 status = invoke(h,'Write',int16(v1)); 910 % send value from sld2 11 v2 = round(get(sld2,'value'));12 status = invoke(h,'Write',int16(v2)); 1314 % send value from sld3 15 v3 = round(get(sld3,'value'));16 status = invoke(h,'Write',int16(v3)); 1718 % send reset pulse 19 status = invoke(h,'Write',int16(2989));20 21 % close rtdx port22 status = invoke(h,'Close');
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Line 7 retrieves the value from the slider using the get function to retrieve the value property. The value is then rounded off to create an integer, and the integeris sent as an 16-bit quantity to the DSP in Line 8. The other two sliders are sent in the same way. Line 19 sends 2989 to the DSP, which can be used toindicate that the three previously-transmitted values represent a complete set of data points. ( You can use whatever value you want. ) This can be used to prevent the DSP and Matlab from losing synchronization if a transmittedcharacter is not received by the DSP and provides some error detection.

Line 22 closes the RTDX port. Make sure you close the port after sending a data block to the DSP.

Advanced features

The slider example shows some basic features of the gui tools. The handle for the RTDX server is generated into the workspace so that it can be used for writing. But other elements, such as text boxescannot be dealt with as easily. The Parameters from these can be accessed through their returned handles. Some examples:

%GUI.m %****Sample GUI, Text and a Button***%open a blank figure Fig = figure(1);set(Fig,'Name','Test GUI'); %Space to enter texted2 = uicontrol(Fig,'backgroundcolor','white','units','Normalized','pos',[.1,.6,.4,.05],...'string','Default Text','style','edit'); %Buttonbut1 = uicontrol(Fig,'foregroundcolor','blue','units','Normalized','pos',[.1,.4,.5,.1],...'string','Press Me!','style','pushbutton','callback','SampleGUI');

A Text box is created with default text in it that says: "Defaul Text". A button is also created, which when pressed, will execute the callback function SampleGUI.m

%SampleGUI.m %Get TexttestText = get(ed2,'string')

Now testText holds whatever string was entered into the text box. The function get() is used to retrieve the data from the 'string; parameter in the ed2 handle. MATLAB help uicontrol gives the full list of options for interface elements.

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Questions & Answers

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
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
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.
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Source:  OpenStax, Digital signal processing laboratory (ece 420 55x). OpenStax CNX. Jan 18, 2010 Download for free at http://cnx.org/content/col10397/1.10
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