EVAL-AD7707EB Datasheet, PDF (8/16 Pages) Analog Devices – Evaluation Board for the AD7707 3V/5V, +/-10V Input Range, 1mW, 3Channel, 16-Bit, Sigma Delta ADC

EVAL-AD7707EB
The Program AD7707 Screen
Fig. 5. shows the screen that appears when the Program AD7707 button is selected. This screen allows the user to select which
register is to be programmed. Before selecting any of the buttons on this screen the user should first choose the channel that
is to be used for all the subsequent operations. The state of the Standby bit should also be selected here.
The Setup Register Screen
Fig. 6. shows the Setup Register screen. When the screen is loaded the software will read the current contents from the Setup
Register of the AD7707 and change the option buttons accordingly. The setup register is used to change the operating mode
of the AD7707, change the gain setting, set the part to bipolar or unipolar mode, set the part to buffered or unbuffered mode
and select the state of the FSYNC bit. Every time a change is made the software will write the new conditions to the AD7707
and read back the setup register for confirmation.
Fig. 6. The Setup Screen
When the user selects a calibration, the software will start the calibration by writing to the AD7707 and then monitor the
DRDY. A falling edge of the DRDY pin will indicate that the calibration has been completed. After a calibration the AD7707
returns to its normal operating mode and the program updates the screen to indicate this. The default status for the setup
register on power-up is 01 (hex).
The Clock Register Screen
Fig. 7. shows the Clock Register setup screen. The Clock Register is used to control the output update rate of the AD7707.
The CLKDIS bit is used to control the operation of the MCLKOUT pin.
A logic 0 in this bit allows the AD7707 to function in its normal operating mode when a crystal oscillator is used as the clock
source.
A logic 1 disables the MCLKOUT from appearing at the pin. When disabled the MCLKOUT pin is forced low. If the AD7707
is using a crystal oscillator as the clock then disabling the MCLKOUT will stop the clock and no conversions will be done
by the AD7707. The user should consult the datasheet for more information on the use of the CLKDIS bit.
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