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Program Description
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.
3.3.2 Reference Section
The touch screen function is always performed using a ratiometric or differential mode on this EVM set to
obtain better touch readings. For all other A/D functions (non-touch measurements such as BAT), a
reference voltage is needed for the A/D converter. Figure 8 shows this section with the TSC2111 internal
reference chosen.
The internal reference voltage can be set to either 1.25 V or 2.5 V. The internal reference powers down
between conversions to save power. The Powered at all times checkbox overrides this feature, and the
reference does not power down. If the reference is allowed to power down, the TSC2111 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 can be selected as shown in Figure 9 . The value of the external
reference should be entered in the text box shown.
Figure 9. Configuration Screen With External Reference Selection
TSC2111EVM and TSC2111EVM-PDK14 SLAU178 – April 2006
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