Generating a Sine Wave Using the Hardware and Software
Tools for the TI TMS320C6748 DSP
Aim of the Experiment
The aim of this experiment is to
- become familiar with the TMS320C6748 hardware and software tools
by outputting sinusoidal signals from the C6748 board and
- explore the design tradeoffs in signal quality vs. implementation
complexity in computing values of sinusoidal signals.
Design tradeoffs in computing sinusoidal signal values are explained in a
lecture 1 slides.
Sinusoidal waveforms will be output by using two different methods:
Equipment to be checked out
- Two BNC - stereo pin (DSP)cables
- C6748 DSP Experimenter's Kit
All the above equipment can be checked out from the checkout counter
on the second floor.
The above list of equipment is the equipment required per work station.
Deviations from the laboratory manual
- Care should be taken that the sine wave samples that are
generated are by the sin() function are properly
converted into 16-bit integers so that the AIC recognizes
it as data.
- To measure the frequency of the sine wave generated use the
oscilloscope. The other method using the signal generator
can be ignored.
- We will use direct memory access (DMA) in a later laboratory
assignment.
- Please obtain the number of clock cycles required for generation
of a sinusoid by using the Code Composer profiler according to the
Wiki
instructions.
Downloads
Recitation Slides
Part 1 and
Part 2
by Ms. Debarati Kundu, The University of Texas at Austin
Lab #2 Handout explaining
polling and interrupts, C6748 code for lab #2, and the
requirements for the lab report (updated Sep. 11, 2011)
TI C6748 DSP files
for lab #2 as a single zip file
(7-zip free zip program)
LabVIEW transmitter demonstration to show how labs 1-6 fit together
Overview Slides,
by Prof. Steven Tretter, University of Maryland (from Jan. 2008 lab manual)
OLD: LabVIEW Virtual instrument for test and
measurement of results on the C6713 DSK.
Debugging and Troubleshooting Tips
Here are troubleshooting tips if you see an incorrect sinusoid on the
oscilloscope:
- Be sure that the output impedance of the signal generator is set
to be high-Z.
- Check the implementation of the difference equation or lookup
table method.
One can use the printf function to print out the values
of samples they generated so they can check the correctness.
- Be sure that the sampling rate is set properly in both the
Interrupt Service Routine (ISR) and the configuration file.
The sampling frequency specified in isr file is only used for
computation.
- Check to see if interrupt is working.
Even though the interrupt is not working, the oscilloscope could
still show sinusoidal-like noise.
This can be easily checked by measuring the magnitude of the
waveform, and knowing that noise should have a very small magnitude.
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