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This process has shown you how to set breakpoints and single-step through Java code.

What happens if you try to step into the process() function?

The debugger will step over the function because it is written in C.

Debugging in c

Debugging in C is done using ndk-gdb , which is supported in Eclipse. To do this, first terminate any existing debug session and then on the Android device, exit the current application by hitting the home button.

To configure GDB, switch back to the C/C++ Perspective and do the following:

  1. Click Run>Debug Configurations...
  2. Select Android NDK Application and press the New icon, and rename the configuration to Lab4 (1) .
  3. On the Android tab:
    1. Under Project , hit Browse... and select the current project.
    2. Under Misc. , select Attach to the running application .
  4. On the Debugger tab:
    1. Select the GDBserver Settings tab.
    2. Use the APK bundled GDBserver.
  5. Apply the settings and Close .

In order to launch GDB, you must first run the application on the Android device, and then attach GDB to the running application. To do this:

  1. Set a breakpoint inside the for loop in process.c .
  2. Click Run>Run . You should see the application launch on the Android device, ignoring any Java breakpoints that you have set.
  3. After the application starts, click Run>Debug As...>Android NDK Application . The Debug Perspective should launch again, but this time with gdbserver debugger . The processor will halt at the set C breakpoint.
If Android NDK Application does not show up, make sure that Lab 4 is highlighted in the Project Explorer before trying to launch the debugger.

In the Expressions window, the sb.get(0) (which is a Java method) will have generated an error as we are now debugging in C. Verify that inBuf has the same values as the test vector look-up table by adding inBuf[0] to the list of expressions; check several different array indices.

Exporting variables to a file

A useful feature that is fully supported in CCS is the ability to export processor memory to a file, which can then be imported into MATLAB for further analysis. To enable this feature in Eclipse, the lab machines have the eVars plugin installed. As an example, to export the inBuf array to file:

  1. In the Debug Perspective , go to Window>Show View>Variables .
  2. Right-click on the inBuf pointer and select Display as Array .
  3. Click the Expand Variables icon multiple times until the entire array has been expanded.
  4. Once the array is fully expanded, click on the Export Variables icon, and save to a txt file.
  5. Use evars2array.m to read in the text file into a MATLAB vector.

In the next lab, we will see how to create and write to a file on the Android device, and use adb to download this file to the host machine, directly from MATLAB.

Part 3: a spectrogram algorithm in matlab

As an initial step towards implementing the spectrogram in Android, you will first implement it in MATLAB. [link] shows the components that your spectrogram algorithm should have; the ability to overlap, while important, will be left for extra credit, and is therefore optional.

Spectrogram components

Overlap->Window->Zero-pad->FFT->Magnitude squared->log()

If you need to see an existing implementation, type open spectrogram in the MATLAB prompt. This will open the spectrogram function you used in the Prelab.

Questions & Answers

how do you translate this in Algebraic Expressions
linda Reply
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Shanjida
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
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Cied
types of nano material
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
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
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what is system testing?
AMJAD
preparation of nanomaterial
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
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AMJAD
what is the application of nanotechnology?
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
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
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
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
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Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
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the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
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Smarajit Reply
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Source:  OpenStax, Ece 420 spring 2014. OpenStax CNX. Jan 18, 2014 Download for free at http://cnx.org/content/col11618/1.3
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