sx8661 Semtech Corporation, sx8661 Datasheet - Page 60

• Manufacturer Part Number: sx8661
• Description: Low Power, Capacitive Button Touch And Proximity Controller 8 Sensors With Led Drivers And Analog Output
• Manufacturer: Semtech Corporation

ADVANCED COMMUNICATIONS & SENSING
AoiLevelBtn0,
AoiLevelBtn7, AoiLevelIdle
Revision v3.2, January 2011
or:
These registers define the level that will be output on AOI-A or AOI-B (depending on button mapping) when the
corresponding button is touched or when the corresponding state is active or idle. The duty cycle is defined as
a number of steps.
The mean voltage of a PWM signal is given by:
AoiPwmPeriod is 255 or 63.
Example:
When button 0 is touched the desired AOI voltage is 0.30 Volts.
To calculate the AoiLevelBtnx is as follows (with AoiPwmPeriod=255):
Assuming a 3.3V VDD:
Mean voltage
AoiLevelBtnx
AoiLevelBtnx
Write 0x17 in the register AoiBtn0DutyCycle.
AoiLevelBtn1,
≈
≈
(Mean voltage / Maximum Voltage (VDD)) * AoiPmwPeriod
(AoiLevelBtnx / AoiPmwPeriod) * Maximum Voltage (VDD)
≈
≈
(Mean voltage / Maximum Voltage (VDD)) * AoiPmwPeriod
(0.3/3.3) * 255
AoiLevelBtn2,
Low Power, Capacitive Button Touch and Proximity Controller
≈
23 decimal
© 2011 Semtech Corp.
AoiLevelBtn3,
60
(8 sensors) with LED Drivers and Analog Output
AoiLevelBtn4,
AoiLevelBtn5,
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DATASHEET
AoiLevelBtn6,
SX8661