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4 Software
Once the ADS1271EVM-PDK software (described in Step 4 ) is installed, evaluation and development with
the ADS1271 can begin.
4.1 Basic Usage
Once the evaluation software is started, it checks to see whether an MMB0 is connected. If hardware is
connected and recognized, the program downloads the firmware to it, and continues to operate. If no
hardware is detected, a dialog box is displayed telling you that it cannot find an MMB0. If you see this,
make sure the MMB0 is connected and powered on and click
Retry . If the software cannot find the
hardware, you can click Cancel to quit the application.
After the program loads the MMB0 successfully, you will see a screen similar to that shown in Figure 2 .
The top portion of the display shows an FFT of the ADC data and certain AC analysis numbers.
Immediately below the FFT graph (middle portion of the display) are a number of controls and meters. At
the bottom of the display is a set of tabs, which show either a histogram, a picture of the incoming
waveform, or the data recording controls.
To exit the program, select File → Exit from the menu bar.
When the program starts, it will be in idle mode. You can put it in either Acquire Mode or Record Mode .
4.1.1 Acquire Mode
In Acquire mode, the ADS1271EVM software collects data from the board in 2,048-sample blocks and
performs the appropriate analysis. Both AC and DC analyses are performed.
To put the program into Acquire mode, click the Acquire button.
In Acquire mode, you can only view the data from one channel at a time. To choose channels, use the
Channel box.
4.1.1.1 AC Analysis
The basic AC analysis consists of the FFT graph and THD calculations. The THD analyzer uses an
automatic tone-detection algorithm, which searches for the highest harmonic to use for the THD analysis.
The detected frequency is shown in the indicator marked
Tone Freq .
NOTE: For the THD analysis to work, the input must be a sine wave below half the Nyquist
frequency, since the THD analyzer needs at least one harmonic for correct operation.
4.1.1.2 Time Domain Analysis
The ADC data is plotted as a waveform in the time domain on the Waveform tab located at the bottom of
the screen.
4.1.1.3 DC Analysis
For DC analysis, the middle section of the application provides DC RMS noise (standard deviation), peak
amplitude, and a DC level meter.
A histogram of the ADC data is plotted on the Histogram tab located at the bottom of the screen. Basic
DC measurements work best when the ADC is driven by an amplifier, stable voltage source, or by shorting
the inputs.
4.1.2 Record Mode
To record/save ADC data, go to the Record To File tab and do the following:
1. If Acquire is on, turn it off. You must stop acquisition before the record feature can be enabled.
2. Enter acquisition settings using the Conversion Mode drop-down control and Sample Rate field. The
Channel selector can be ignored since it has no effect during data recording.
6 ADS1271EVM and ADS1271EVM-PDK User's Guide SBAU107C – November 2004 – Revised November 2014
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