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SECTION 2
RUNNING THE DEMONSTRATION FILE
MOTOROLA
DSP56303EVMUM/AD, Preliminary
2-1
Running the Demonstration File
2.1
2.2
2.3
OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
SETTING UP THE DEMONSTRATION . . . . . . . . . . . . . . . . 2-3
RUNNING THE DEMONSTRATION . . . . . . . . . . . . . . . . . . . 2-4
2-2
DSP56303EVMUM/AD, Preliminary
MOTOROLA
Running the Demonstration File
Overview
2.1
OVERVIEW
This section describes the demonstration that is included with the DSP56303EVM.
The demonstration is designed to show the advantage of 24-bit DSPs over 16-bit
DSPs. Even if the system input data is limited by a 16-bit data converter, the system
can still benefit greatly from using the 24-bit DSP architecture.
This demonstration takes an input signal, digitizes it, and adds a 60 Hz tone to
simulate the noise that can be generated by a 60 Hz AC power line. The signal is then
filtered using one of three sets of coefficients.
The first set of coefficients performs no filtering, simply allowing the corrupted
signal to pass through. The second set of coefficients use 24-bit coefficients to
correspond to a 60 Hz notch filter that removes the 60 Hz portion of the corrupted
signal. The final set of coefficients are the same as those used for the 24-bit filtering,
only rounded to 16 bits.
The following sections give step-by-step instructions on how to run this demo.
2.2
SETTING UP THE DEMONSTRATION
Perform the following steps to set up the demonstration:
1. Set up the audio source, preferably a music source with a headphone output,
such as a portable radio, tape player, or CD player.
2. Make sure the DSP56303EVM has been installed and tested, as described in
Section 1
.
3. Using the cable with the 1/8-inch stereo plugs, connect the output of the audio
source to the stereo input jack labelled P3/IN on the DSP56303EVM.
4. Connect a pair of headphones to the stereo headphone jack labelled
P4/HDPHNE on the DSP56303EVM. Refer to
Figure 2-1
for the locations of
the line input and headphone jacks.
Start the audio source and put on the headphones.
MOTOROLA
DSP56303EVMUM/AD, Preliminary
2-3
Running the Demonstration File
Running the Demonstration
MC145407
JTAG/
OnCE
J3
J9
J8 ISA CONNECTOR Timer
LED
MCM6306
J6
ESSI1/SCI
SW1
DSP56303
Reset
MC34164
IRQA
J2
SW2
J5 JTAG
SW3
IRQD
P4
HDPHNE
P5
OUT
MCM6306
DSP56002
P1
Command
Converter
AT29LV512
PEROM
MCM6306
SRAM
J1
J4
POWER
P2
Debug
LED
J7 ESSI0
LT1085
COMMAND CONVERTER SELECT
MC74HCT241
MC74HCT04
Power
LED
CS4215
Codec
MC33078
P3
IN
LT1085
Serial #
Figure 2-1
DSP56303EVM Component Layout
2.3
RUNNING THE DEMONSTRATION
To run the demonstration:
1. Start Windows.
2. Invoke the Debugger by double-clicking on the icon labelled
evm30xw
in the
evm5630x
program group.
3. Click on the command window and type
force r
to reset the DSP56303 and
enter the debug mode.
4. Type in
load 60hzdemo
to load the demonstration file into the DSP56303.
5. Finally, type
go
to begin the demonstration. The first set of coefficients (no
filtering) is used when the demonstration begins. The first set of coefficients
performs no filtering, simply allowing the corrupted signal to pass. Thus, the
output contains the input signal with the added 60 Hz tone when the demo
begins.
2-4
DSP56303EVMUM/AD, Preliminary
MOTOROLA
Running the Demonstration File
Running the Demonstration
6. Briefly press SW2 to invoke external internal request A (IRQA). Invoking
IRQA causes the DSP to use the 24-bit filter coefficients. Refer to
Figure 2-1
for
the location of SW2.
7. To hear the results of using the 16-bit coefficients, briefly press the switch
labeled SW3. This invokes the external interrupt request D (IRQD), which
causes the DSP to use the 16-bit filter coefficients. Refer to
Figure 2-1
for the
location of SW3.
Note:
You will hear a significant difference between filtering with the 24-bit and
16-bit coefficients. The reason for this contrast is that it is impossible to
place the notch of the filter exactly on 60 Hz with 16-bit coefficients. The
16-bit filter notch is slightly offset and, therefore, misses the frequency of
the noise. With the 24-bit coefficients, it is possible to place the filter notch
exactly on 60 Hz.
8. To stop the execution of the demo, type
force r
in the command window in the
bottom left corner of the screen.
9. To exit the Debugger, type
quit
.
MOTOROLA
DSP56303EVMUM/AD, Preliminary
2-5

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