AR1000_16 Datasheet, PDF (25/61 Pages) Microchip Technology – AR1000 Series Resistive Touch Screen Controller

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER
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
sensitivity. 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
measurement sample averaging, when touch
movement is determined to be fast. See the
SpeedThreshold register 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
measurement 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-
frequency 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-
frequency 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
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DS40001393C-page 25