AN101
© Kionix 2019 All Rights Reserved
11 July 2019
Page 11 of 27
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Write 0x01 to Control 5 (CNTL5) to for the sensor into sleep mode (MAN_SLEEP=1).
Register Name
Address
Value
CNTL5
0x1F
0x01
-
Write 0x05 to Wakeup Function Counter (WUFC) to set the time motion must be present for
0.1 second before a Wake-up interrupt is triggered. The following formula is used:
WUFC (counts) = Desired Delay Time (sec) x OWUF (Hz)
WUFC (counts) = 0.1 sec x 50 Hz = 5 counts
Register Name
Address
Value
WUFC
0x4D
0x05
-
Write 0x80 to the Wakeup Function Threshold (WUFTH) and 0x00 to Back to Sleep Wakeup
Function Threshold (BTSWUFTH) to set the wakeup threshold to 0.5g.
WUFTH (counts) = Wake-Up Threshold (g) x 64 (counts/g)
WUFTH (counts) = 0.5g * 64 counts/g = 32 (0x20) counts
Register Name
Address
Value
WUFTH
0x49
0x20
BTSWUFTH
0x4A
0x00
-
Write 0xE0 to Control 1 (CNTL1) to set the accelerometer into operating mode (PC1=1), full
power mode (RES=1), data ready enabled (DRDYE=1), range to ±8g (GSEL=0).
Register Name
Address
Value
CNTL1
0x1B
0xE0
-
Monitor the physical interrupt INT1 of the accelerometer, if the acceleration input profile
satisfies the criteria previously established for the 0.5g motion detect threshold level in both
positive and negative directions of the X, Y, Z axis for more than 0.1 second, then there
should be positive latched interrupt present. Also, the WUFS bit in Interrupt Status 3 (INS3)
will be set to indicate the wake-up interrupt has fired. INS3 also provides information
regarding which axis/axes caused the wakeup interrupt. Finally, WAKE bit in Status (STAT)
will also be set to indicate the sensor is in WAKE mode.
Register Name
Address
Value
INS3
0x18
ins3
if
(ins3 & 0x80)
{
// handle wakeup event
}
