Datasheet

UG-215 Evaluation Board User Guide
Rev. A | Page 4 of 12
AD5543 EVALUATION SOFTWARE WINDOW
LEVEL SET
The LEVEL SET section in the AD5543 evaluation software
allows you to choose the amplitude for the waveform depending
on the code entered in the Input Data box. Click the Write To
DAC button to load the code. Being a 16-Bit DAC, the relation-
ship between the code entered and the voltage in the output is
as follows:
REF
N
OUT
V
D
V ×−= )1
2
(
where:
N = 16 bits.
V
REF
= 5 V.
D is the code introduced in decimal (0 to 32,767).
Waveform Generation
The WAVEFORM GENERATION section allows you to
control the different frequencies and features in the waveform
generation, including
• SCLK: clock input frequency (30 MHz default value).
• Waveform Frequency (Fo).
• Signal Type: dc signal (default), sawtooth, sine, triangle,
and square wave options.
• Sampling Information includes the two following features:
• Sampling Frequency (Fs): to avoid the aliasing effect,
it is necessary to choose a frequency that is at least
twice the value of the waveform frequency. The
number of points sampled is calculated as follows:
FrequencyWaveform
FrequencySampling
SampledPointsofNumber =
• Number of Samples (s): this constant allows you to
show in a graph a determined number of periods
depending on its value. The maximum number of
samples is 32,768.
SampledPointsofNumber
samplesofNumber
PeriodsofNumber =
• Data Loaded to DAC: the array contains the value of every
code where the waveform has been sampled.
• The graph shows each of the points contained in the array.
Example 1
1. Power on the board.
2. Start up the software.
3. Select the default 30 MHz clock frequency.
4. Select a waveform frequency of 500 Hz and Sine Wave as
the signal type to show (dc signal is the default).
5. Select a sampling frequency of 20 kHz and 80 for the
number of samples.
40
Hz500
Hz000,20
==SampledPointsofNumber
2
40
80
==PeriodsofNumber
6. Write the Code FFFF to show full scale.
7. Click Wr i te To DAC.
The waveform obtained from the values entered shows two
periods and the 40 samples per period (see Figure 3). The code
of each sample is loaded in the array on the right side.
Click the STOP button to end the execution of the software.
Example 2
For a sharper waveform, the sampling frequency and the
number of samples must be raised according to the frequency.
The next example (see Figure 4) shows this relationship, where
the sampling frequency value is changed to 1 MHz and the
number of samples is 2000.
2000
Hz500
Hz000,000,1
==SampledPointsofNumber
1
2000
2000
==PeriodsofNumber