MXT641T datasheet(20/74 Pages) ATMEL

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mXT641T 1.0 [Datasheet]

9917JX–AT42–02/15

Sensor Layout

The specific electrode designs used in Atmel touchscreens are the subject of various patents and patent applications.

Further information is available on request.

The physical matrix can be configured to have one or more touch objects. These are configured using the appropriate

touch objects (Multiple Touch Touchscreen and Key Array). It is not mandatory to have all the allowable touch objects

present. The objects are disabled by default so only those that you wish to use need to be enabled. Refer to the

mXT641T 1.0 Protocol Guide for more information on configuring the touch objects.

The device supports various configurations of electrodes as summarized below:



Touchscreen: 32 X × 20 Y maximum (subject to other configurations)



Keys: Up to 32 keys in an X/Y grid

When designing the physical layout of the touch panel, obey the following rules:



Each touch object should be a regular rectangular shape in terms of the lines it uses.



The touch objects cannot share X and Y lines



It is recommended that the touchscreen should start at X0, Y0; if self-capacitance measurements are enabled, the

touchscreen must start at X0, Y0



It is recommended that the keys should occupy the highest X and Y lines

For optimal performance in terms of cycle time overhead, it is recommended that the number of X (drive) lines used is

kept to the minimum and designs should favor using Y lines where possible. Figure 6-1 shows an example layout for

1 X × 4 Y lines. Note that in this case using 1 X × 4 Y lines would give better performance than using 4 X × 1 Y lines.

Figure 6-1. Example Layout – Optimal Cycle Time

X30

X31

Y19

Y16

Y15

Multiple Touch

touchscreen

(31 X × 16 Y)

Keys

1 X × 4 Y

MXT641T Datasheet(PDF) 20 Page - ATMEL Corporation