Evaluation Board
User Guide
Rev. A | Page 10 of 14
Multichip Sync Control
The
Multi-Chip Sync
control allows you to set up the sync
function. This allows you to synchronize multiple chips to
one master AD9915. Refer to the AD9915 data sheet for a
full discussion on multichip sync functions. The
Sync out
enable
checkbox allows activation of SYNC_OUT pin.
Default value is disabled. To enable multi-chip
synchronization, select
Multi-chip sync
.
SYNC IN delay
drop-down menu allows the user to delay the SYNC_IN
signal by programming the 3-bit word.
SYNC OUT
delay
can also be programmed.
PROFILE MODE
In Profile Mode, the DDS signal control parameters are
supplied directly from the profile programming registers. A
profile is an independent register that contains the DDS
signal control parameters.
SINGLE-TONE OPERATION
For single tone operation, follow these steps:
1)
Power-up the AD9915 evaluation board (Refer to
power connections in this user guide).
2)
Put REF CLK source for the REF CLK input.
(Refer to datasheet for reference frequency values).
3)
Load the AD9915 evaluation software.
4)
Click the Master reset ICON.
Note: Every time you connect an evaluation
board, always do the Master Reset. This clears
all memory elements and sets registers to default
values.
5)
Enter desired REF CLK frequency value in
External Clock window.
6)
Click DAC CALIBRATION ICON.
Note this ICON must be clicked for all initial
setups andevery time the REF CLK frequency is
changed.
7)
Click the profile tab to go to the profile windows.
8)
Enable profile mode via check box and enter the
desired output frequency in profile 0.
9)
Click the flashing LOAD button top of GUI.
10)
View the DAC output performance via oscilloscope
or spectrum analyzer.
There are eight profile registers (Profile 0 – Profile 7) that
are available but only a single profile can be loaded to the
DDS at a time. They cannot be loaded simultaneously.
To load a profile, check first the
Enable Profile Mode
checkbox and then select a profile at the
Selected Profile
drop-down menu .
Data Entry
Frequency
is used to set the frequency generated by the
DDS. The input values are in MHz (refer to datasheet for
acceptable range of output frequencies)
Phase Offset
controls the phase of the DDS output. The
input is in degrees and this can be changed from 0° to 360°
with 16-bit resolution.
Amplitude Scale Factor
digitally controls the amplitude of
the carrier from the DDS. This scalar ranges from 0 to 1 and
has a 12-bit resolution. Note that this function only works if
the
OSK enable
is activated in the
Control Tab
.
Note that Frequency, Phase Offset, and Amplitude Scale
Factor can accept native data that are going to be loaded
directly to the registers. This data is binary in form but can
also be expressed as hexadecimal, or decimal. This can be
done by pressing the drop-down button at the side of each
input
.
Figure 10. Default Profile Display
Figure 11. Profile Data Entry Expanded
