sx8638 Semtech Corporation, sx8638 Datasheet - Page 43

• Manufacturer Part Number: sx8638
• Description: Low Power, Capacitive Button And Slider Touch Controller 8 Sensors With Enhanced Led Drivers And Proximity
• Manufacturer: Semtech Corporation

ADVANCED COMMUNICATIONS & SENSING
CapModeMisc
CapMode7_4, CapMode3_0:
Revision 7_6, September 10
Capacitive Sensors Parameters
Address
0x1F
0x70
By default the ASI is using a common sensitivity for all capacitive sensors as in the usual case overlay material
and sensors sizes are about equal. The register bits CapSensitivity0_1[7:4] determine the sensitivity for all
sensors in common sensitivity mode.
It might be required to have a different, individual, sensitivity for each CAP pin (for example proximity sensor
set to max sensitivity while touch sensors are set to a lower one). This can be obtained by setting
CapModeMisc[2:0] to “100” The individual sensitivity mode results in longer sensing periods than required in
common sensitivity mode.
The CAP pins can be set as a button, part of a slider or disabled depending on the application.
Name
CapPerComp
CapProxEnable
buttons
slider
Bits
7:4
3:0
7:0
Table 15
(of four sensors)
Description
Reserved
Periodic Offset Compensation
Enables proximity sensing:
0x46: OFF
0x74: ON
Table 16 Possible
minimum
zero
one
© 2010 Semtech Corp.
Capacitive Sensors Parameters
Low Power, Capacitive Button and Slider Touch Controller
(8 sensors) with Enhanced LED Drivers and Proximity
43
(of six sensors)
CAP pin modes
default
one
two
Defines the periodic offset compensation.
0x0: OFF (default)
0x1: 1 second
0x2: 2 seconds
…
0x7: 7 seconds
0x8: 16 seconds
0x9: 18 seconds
…
0xE: 28 seconds
0xF: 60 seconds
(of eight sensors)
maximum
four
one
DATASHEET
www.semtech.com
SX8638