UG-459 Datasheet, PDF (5/12 Pages) Analog Devices – Full-featured evaluation board

Evaluation Board User Guide
UG-459
Figure 4. AD568x(R) Evaluation Board Software Main Window
SOFTWARE OPERATION
The software for the AD568x(R) allows the user to program
values to the input and DAC registers of each DAC individually
or collectively.
Write to Input Register
GAIN Control
The logic level of the GAIN pin is set externally by LK4 or LK5.
To display the correct voltage, the gain selection must be set to
match the level of the pin.
Reference Control
Select Write to Input Register to load the value in the input
data control to the input register of any DACs selected in the
Select DACs to Use box.
Write to DAC Register
Select Write to DAC Register to load the value in the input data
control to the DAC register of any DACs selected in the Select
DACs to Use box. The DAC outputs are automatically updated
with the appropriated voltage.
Update DAC Register from Input Register
Select Update DAC Register from Input Register to copy the
value in a DAC input register to the corresponding DAC register.
DAC outputs are automatically updated with the appropriated
voltage.
LDAC CONTROL
Select Pulse LDAC to bring the LDAC pin low and then back
high. Do this copies the data from the input registers to the DAC
registers, and the outputs update accordingly. Any DAC updates
disabled by the LDAC mask settings are ignored.
The AD5686R and AD5684R have an on-chip reference that
can be disabled to reduce power consumption. The AD5686R
and AD5684R software has a control that allows this function to
be used.
The AD5686 and AD5684 require an external reference. The
software for the AD5686 and AD5684 has a control that allows
the user to set the reference voltage.
Power-Down Control
Each of the DACs can be powered down individually. Each of the
DACs has an associated selection box allowing the part to operate
in normal mode, powered down with either a 1 kΩ or a 100 kΩ
resistor to ground or tristate. When the power-down setting for
each DAC are selected, click Write to Part to write the appropriate
values to the AD568x(R).
LDAC Mask Register
Each of the DACs can be set to accept or ignore LDAC pulses.
When the LDAC selections are completed, click Write to Part
to write the appropriate values to the AD568x(R).
The LDAC pin can also be set high or low by clicking the
appropriate radio button.
SPI COMMAND
On both control tabs of the software, the SPI commands sent to the
DAC display. This shows what must be written to the AD568x(R)
to replicate the function of the evaluation board.
Rev. 0 | Page 5 of 12