Datasheet

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER
DS41393B-page 30 Preliminary  2009-2012 Microchip Technology Inc.
8.2 Register Descriptions
8.2.1 TouchThreshold Register (OFFSET
0x02)
The TouchThreshold register sets the threshold for a
touch condition to be detected as a touch. A touch is
detected if it is below the TouchThreshold setting. Too
small of a value might prevent the controller from
accepting a real touch, while too large of a value might
allow the controller to accept very light or false touch
conditions. Valid values are as follows:
0 ≤ TouchThreshold ≤ 255
8.2.2 SensitivityFilter Register (OFFSET
0x03)
The SensitivityFilter register sets the level of touch sen-
sitivity. A higher value is more sensitive to a touch
(accepts a lighter touch), but may exhibit a less stable
touch position. A lower value is less sensitive to a touch
(requires a harder touch), but will provide a more stable
touch position. Valid values are as follows:
0 ≤ SensitivityFilter ≤ 10
8.2.3 SamplingFast Register (OFFSET
0x04)
The SamplingFast register sets the level of touch mea-
surement sample averaging, when touch movement is
determined to be fast. See the SpeedThreshold regis-
ter for information on the touch movement threshold. A
lower value will provide for a higher touch coordinate
reporting rate when touch movement is fast, but may
exhibit more high-frequency random noise error in the
touch position. A higher value will reduce the touch
coordinate reporting rate when touch movement is fast,
but will reduce high-frequency random noise error in
the touch position. Valid values are as follows:
SamplingFast: <1, 4, 8, 16, 32, 64, 128>
Recommended Values: <4, 8, 16>
Higher values may improve accuracy with some
sensors.
8.2.4 SamplingSlow Register (OFFSET
0x05)
The SamplingSlow register sets the level of touch mea-
surement sample averaging, when touch movement is
slow. See the SpeedThreshold register for information
on the touch movement threshold. A lower value will
increase the touch coordinate reporting rate when the
touch motion is slow, but may exhibit a less stable more
jittery touch position. A higher value will decrease the
touch coordinate reporting rate when the touch motion
is slow, but will provide a more stable touch position.
Valid values are as follows:
SamplingSlow: 1, 2, 4, 8, 16, 32, 64, 128
8.2.5 AccuracyFilterFast Register (OFFSET
0x06)
The AccuracyFilterFast register sets the level of an
accuracy enhancement filter, used when the touch
movement is fast. See the SpeedThreshold register for
information on the touch movement threshold. A lower
value will provide better touch coordinate resolution
when the touch motion is fast, but may exhibit more
low-frequency noise error in the touch position. A
higher value will reduce touch coordinate resolution
when the touch motion is fast, but will reduce low-fre-
quency random noise error in the touch position. Valid
values are as follows:
1 ≤ AccuracyFilterFast ≤ 8
Higher values may improve accuracy with some
sensors.
8.2.6 AccuracyFilterSlow Register
(OFFSET 0x07)
The AccuracyFilterSlow register sets the level of an
accuracy enhancement filter, used when the touch
movement is slow. See the SpeedThreshold register for
information on the touch movement threshold. A lower
value will provide better touch coordinate resolution
when the touch motion is slow, but may exhibit more
low-frequency noise error in the touch position. A
higher value will reduce touch coordinate resolution
when the touch motion is slow, but will reduce low-fre-
quency random noise error in the touch position. Valid
values are as follows:
1 ≤ AccuracyFilterSlow ≤ 8
8.2.7 SpeedThreshold Register (OFFSET
0x08)
The SpeedThreshold register sets the threshold for
touch movement to be considered as slow or fast. A
lower value reduces the touch movement speed that
will be considered as fast. A higher value increases the
touch movement speed that will be considered as fast.
Valid values are as follows:
0 ≤ SpeedThreshhold ≤ 255