Freescale Semiconductor FRDM-FXS-MULTI Datenbogen
MMA8652FC
Sensors
38
Freescale Semiconductor, Inc.
6.8.3
0x16: FF_MT_SRC Freefall/Motion Source register
The Freefall/Motion Source register keeps track of the acceleration event that is triggering (or has triggered, if ELE bit in
FF_MT_CFG register is set to 1) the event flag. In particular, EA is set to 1 when the logical combination of acceleration events
flags specified in FF_MT_CFG register is true. This EA bit is used in combination with the values in INT_EN_FF_MT and
INT_CFG_FF_MT register bits to generate the freefall/motion interrupts.
FF_MT_CFG register is set to 1) the event flag. In particular, EA is set to 1 when the logical combination of acceleration events
flags specified in FF_MT_CFG register is true. This EA bit is used in combination with the values in INT_EN_FF_MT and
INT_CFG_FF_MT register bits to generate the freefall/motion interrupts.
•
An X,Y, or Z motion is true when the acceleration value of the X or Y or Z channel is higher than the preset threshold value
defined in the FF_MT_THS register.
defined in the FF_MT_THS register.
•
An X, Y, and Z low event is true when the acceleration value of the X and Y and Z channel is lower than or equal to the preset
threshold value defined in the FF_MT_THS register.
threshold value defined in the FF_MT_THS register.
Table 51. 0x16: FF_MT_SRC Freefall/Motion Source register (Read-Only)
Back to Register Address Map
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
EA
—
ZHE
ZHP
YHE
YHP
XHE
XHP
Table 52. Freefall/Motion Source register
Bit(s)
Field
Description
7
EA
Event Active flag
0 No event flag has been asserted (default)
1 One or more event flags has been asserted.
0 No event flag has been asserted (default)
1 One or more event flags has been asserted.
See the description of the OAE bit to determine the effect of the 3-axis event flags on the EA bit.
6
—
5
ZHE
Z-Motion flag
ZHE bit always reads zero if the ZEFE control bit is set to zero.
0 No Z motion event detected (default)
1 Z motion has been detected
ZHE bit always reads zero if the ZEFE control bit is set to zero.
0 No Z motion event detected (default)
1 Z motion has been detected
4
ZHP
Z-Motion Polarity Flag
ZHP bit always reads zero if the ZEFE control bit is set to zero.
0 Z event was positive g (default)
1 Z event was negative g
ZHP bit always reads zero if the ZEFE control bit is set to zero.
0 Z event was positive g (default)
1 Z event was negative g
3
YHE
Y-Motion Flag
YHE bit always reads zero if the YEFE control bit is set to zero.
0 No Y motion event detected (default)
1 Y motion has been detected
YHE bit always reads zero if the YEFE control bit is set to zero.
0 No Y motion event detected (default)
1 Y motion has been detected
2
YHP
Y-Motion Polarity Flag
YHP bit always reads zero if the YEFE control bit is set to zero.
0 Y event detected was positive g (default)
1 Y event was negative g
YHP bit always reads zero if the YEFE control bit is set to zero.
0 Y event detected was positive g (default)
1 Y event was negative g
1
XHE
X-Motion Flag
XHE bit always reads zero if the XEFE control bit is set to zero.
0 No X motion event detected (default)
1 X motion has been detected
XHE bit always reads zero if the XEFE control bit is set to zero.
0 No X motion event detected (default)
1 X motion has been detected
0
XHP
X-Motion Polarity Flag
XHP bit always reads zero if the XEFE control bit is set to zero.
0 X event was positive g (default)
1 X event was negative g
XHP bit always reads zero if the XEFE control bit is set to zero.
0 X event was positive g (default)
1 X event was negative g