Datasheet

Program Description

3-18

Average/Median—There are two ways to reduce noise effect to the ADC

result. One is averaging, where 4, 8, or 16 readings are averaged; another

option is to find the median value among 5, 9, or 15 readings. The default

is the average mode, as shown in Figure 3−7. When Median mode is

selected, you see the configuration tab as shown in Figure 3−8.

Figure 3−8. Configuration Screen at Median Mode

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.

3.5.3.2 Reference Section

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 3−7 and Figure 3−8 show this section with the TSC2101 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 if the Powered

at all times checkbox is not checked. Using the Powered at all times checkbox,

this can be overridden and the reference does not power down. If the reference

is allowed to power down, the TSC2101 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.