Texas Instruments ADS1259EVM, User Manual

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Evaluating Performance with the ADCPro Software
There are two power reduction modes that can be used to reduce the quiescent current of the ADS1259
when the part is not in use. They are enabled by clicking the buttons labeled Sleep and Powerdown. In
SLEEP mode, device power is reduced to a minimum; only essential internal functions are kept active.
This condition includes the R
BIAS
status to keep the reference on, if enabled, and some digital function. To
exit SLEEP mode, toggling the button issues the WAKEUP command. The absolute lowest power is
achieved in Power-Down mode. Both SLEEP mode and Power-Down modes can be accessed through the
buttons at the bottom of this tab.
10.1.4 ADC Calibration Tab
A calibration feature is integrated into the ADS1259 to correct for offset and gain errors. The
ADS1259EVM-PDK software is designed to allow the user to use the built-in system calibration
commands or manually calibrate the device by directly entering the values for the offset and gain registers
of the ADS1259.
Figure 33 shows the ADC calibration tab.
Figure 33. ADC Calibration Tab
In the Calibration Options subsection, two buttons allow for an offset calibration and a gain calibration.
First, the offset calibration can be done when the inputs are shorted. As described earlier, the part can be
shorted by setting the three way switch S2 to the right most position labeled CAL, and by setting a jumper
across the left two pins of jumper J15. Then the gain calibration can be performed by keeping the setting
of switch S2 and by moving the jumper to the right side of J15. During calibration, the Working indicator
light shows that the device is performing the calibration and cannot be updated at that time.
At the bottom of this tab, there are two buttons that allow for reading and writing to the Offset Calibration
Register and the Gain (Full-Scale) Calibration Register. To set a register value, enter it into the New
space, and push the Set button. To read back the register push the Read button, and the value is updated
in the space labeled Actual.
29 SBAU163A – March 2010 – Revised April 2010 ADS1259EVM, ADS1259EVM-PDK
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