Texas Instruments TSC2301EVM Evaluation Module TSC2301EVM TSC2301EVM Datenbogen

3-12

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Averaging

Several readings may be taken and then averaged to give a single result.
No averaging can be chosen, or 4, 8, or 16 readings can be averaged.

Note that these settings apply to all operations of the A/D converter, not
just the touch screen operations. Thus, resolution and averaging can be
changed to increase accuracy in the data acquisition functions.

The touch screen function is always performed using a ratiometric mode; for
all other A/D functions, a reference voltage is needed for the A/D converter.
Figure  3-2 shows this section with the TSC2301’s internal reference chosen.
This reference voltage can be set to either 1.2 V or 2.5 V.

The internal reference powers down between conversions, to save power. Us-
ing the Powered at all times checkbox, this can be overidden and the reference
does not power down. If the reference is allowed to power down, the TSC2301
then must allow a delay time for the reference to power up when a conversion
is to take place. This delay time can be set using the slider in this section.

If an external reference is to be used, it may be selected as shown in
Figure  3-3. The value of the external reference should be entered in the text
box shown.

The D/A converter can be powered down by using the checkbox in this section,
if it is not going to be used. If this box is not checked, the D/A converter value