Digital Signal Processing Reference
In-Depth Information
(scaled by 1000). Within the function
main
, another function,
comm_poll
, is
called that is located in the communication and initialization support file
c6713dskinit.c
. It initializes the DSK, the AIC23 codec onboard the DSK, and
the two McBSPs on the C6713 processor. Within
c6713dskinit.c
, the function
DSK6713_init
initializes the BSL file, which must be called before the two sub-
sequent BSL functions,
DSK6713_LED_init
and
DSK6713_DIP_init
,
are
invoked that initialize the four LEDs and the four dip switches.
The statement
while (1)
within the function
main
creates an infinite loop.
When dip switch #0 is pressed, LED #0 turns on and the sinusoid is generated.
Otherwise,
DSK6713_DIP_get(0)
will be false (true if the switch is pressed) and
LED #0 will be off.
The function
output_sample
, located in the communication support file
C6713dskinit.c
, is called to output the first data value in the buffer or table
sine_table[0]
=
0. The loop index is incremented until the end of the table is
reached, after which it is reinitialized to zero.
Every sample period
T
0.125 ms, the value of dip switch #0 is
tested, and a subsequent data value in
sine_table
(scaled by
gain
=
=
1/
F
s
=
1/8000
=
10) is sent
for output. Within one period, eight data values (0.125 ms apart) are output to gen-
erate a sinusoidal signal. The period of the output signal is
T
=
8(0.125 ms)
=
1ms,
corresponding to a frequency of
f
=
1/
T
=
1kHz.
Create Project
In this section we illustrate how to create a project, adding the necessary files for
building the project
sine8_LED
. Back up the folder
sine8_LED
(change its name)
or delete its content (which can be retrieved from the topic CD if needed), keeping
only the C source file
sine8_LED.c
and the file
gain.gel
in order to recreate
the content of that folder. Access CCS (from the desktop).
1.
To create the project file
sine8_LED.pjt
. Select Project
New. Type
sine8_LED
for the project name, as shown in Figure 1.3. This project file is
saved in the folder
sine8_LED
(within
c:\c6713\myprojects
). The
.pjt
file stores project information on build options,
Æ
source filenames,
and
dependencies.
2.
To add files to the project. Select Project
Add Files to Project. Look in the
folder
support
, Files of type C Source Files. Double-click on the C source
file
C6713dskinit.c
to add it to the project. Click on the “
Æ
” symbol to the
left of the Project Files window within CCS to expand and verify that this C
source file has been added to the project.
3.
Repeat step 2, use the pull-down menu for Files of type, and select ASM
Source Files. Double-click on the assembly source vector file
vectors_poll.asm
to add it to the project. Repeat again and select
Files of type: Linker Command File, and add
C6713dsk.cmd
to the project.
+
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