MPR121_10 FREESCALE [Freescale Semiconductor, Inc], MPR121_10 Datasheet - Page 51

• Manufacturer Part Number: MPR121_10
• Description: Proximity Capactive touch Senosr controller
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Sensors
Freescale Semiconductor
The following sections describe what each of the defaults do and recommendations for variations.
Section A
Section B
Register Address
0x7D
0x7E
0x7F
Register Address
Register Address
0x2C
0x2D
0x2B
0x2E
0x2F
0x30
0x31
0x32
Description: This group of setting controls the filtering of the system when the data is greater than the baseline.
Description: This group of setting controls the filtering of the system, when the data is less than the baseline. The
Variation: As the filter is sensitive to setting changes, it is recommended that users read AN3891 before
Variation: As the filter is sensitive to setting changes, it is recommended that users read AN3891 before
AUTO-CONFIG USL Register
AUTO-CONFIG LSL Register
AUTO-CONFIG Target Level Register
MHD Rising
NHD Amount Rising
NCL Rising
FDL Rising
The setting used allow the filter to act quickly and adjust for environmental changes. Additionally, if
calibration happens to take place while a touch occurs, the value will self adjust very quickly. This
auto-recovery or snap back prevents repeated false negative for a touch detection.
changing the values. In most cases these default values will work
MHD Falling
NHD Amount Falling
NCL Falling
FDL Falling
settings slow down the filter as the negative charge is in the same direction as a touch. By slowing
down the filter, touch signals are “rejected” by the baseline filter. While at the same time lon term
environmental change that occur slower than at a touch are accepted. This low pass filter both allows
for touches to be detected properly while preventing false positive by passing environmental change
through the filter.
changing the values. In most cases these default values will work
Register Name
Register Name
Register Name
Value
0x9C
0x8C
0x65
Value
Value
0xFF
0x01
0x01
0x00
0x00
0x01
0x01
0x02
Application Note
AN3889
AN3889
AN3889
Application Note
Application Note
AN3891
AN3891
AN3891
AN3891
AN3891
AN3891
AN3891
AN3891
Section
F
F
F
MPR121
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