sx8644 Semtech Corporation, sx8644 Datasheet - Page 47

• Manufacturer Part Number: sx8644
• Description: Ultra Low Power, Capacitive Button And Slider Touch Controller 12 Sensors With Enhanced Led Drivers
• Manufacturer: Semtech Corporation

ADVANCED COMMUNICATIONS & SENSING
5.4 Button Parameters
Revision 7_3, January 10
Button Parameters
Address
0x21
0x22
0x23
0x24
0x25
0x26
Name
BtnCfg
BtnAvgThresh
BtnCompNegThresh
BtnCompNegCntMax 7:0
BtnHysteresis
BtnStuckAtTimeout
Bits
7:6
5:4
3:2
1:0
7:0
7:0
7:0
7:0
Description
Defines the buttons events reporting method.
00: Multiple reporting of all touches and releases (default)
01: Single reporting of the first button touch. Next button touches and releases are
ignored until release of the first button.
10: Reserved
11: Reserved
Defines the buttons interrupt (for all buttons)
00 : Interrupts masked
01 : Triggered on Touch
10 : Triggered on Release
11 : Triggered on Touch and Release (default)
Defines the number of samples at the scan period for determining a release
00: OFF, use incoming sample (default)
01: 2 samples debounce
10: 3 samples debounce
11: 4 samples debounce
Defines the number of samples at the scan period for determining a touch
00: OFF, use incoming sample (default)
01: 2 samples debounce
10: 3 samples debounce
11: 4 samples debounce
Defines the positive threshold for disabling the processing filter averaging.
If ticks are above the threshold, then the averaging is suspended
0x00: 0
0x01: 4
…
0x50: 320 (default)
…
0xFF: 1020
Defines the negative offset compensation threshold.
0x00: 0
0x01: 4
…
0x50: 320 (default)
…
0xFF: 1020
Defines the number of ticks (below the negative offset compensation threshold)
which will initiate an offset compensation.
0x00: Reserved
0x01: 1 sample (default)
…
0xFF-> samples
Defines the button hysteresis corresponding to a percentage of the CAP thresholds
(defined in Table 18).
0x00: 0%
…
0x0A: 10% (default)
…
0x64: 100%
All buttons use the same hysteresis
Defines the stuck at timeout.
0x00: OFF (default)
Touch Controller (12 sensors) with Enhanced LED Drivers
© 2009 Semtech Corp.
47
Ultra Low Power, Capacitive Button and Slider
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SX8644