Freescale Semiconductor Energy Efficient Solutions Xtrinsic MMA8452Q, Технические данные: Техническая информация

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MMA8452Q
Sensors
32 Freescale Semiconductor, Inc.
6.5 Single, Double and Directional Pulse-Detection Registers
For more details of how to configure the pulse detection and sample code, please refer to Freescale application note, AN4072.
The pulse-detection registers are referred to as “Pulse”.
0x21: PULSE_CFG Pulse Configuration Register
This register configures the event flag for the pulse detection for enabling/disabling the detection of a single and double pulse
on each of the axes.
0x22: PULSE_SRC Pulse Source Register
This register indicates a double or single pulse event has occurred and also which direction. The corresponding axis and event
must be enabled in Register 0x21 for the event to be seen in the source register.
When the EA bit gets set while ELE = 1, all status bits (AxZ, AxY, AxZ, DPE, and PolX, PolY, PolZ) are frozen. Reading the
PULSE_SRC register clears all bits. Reading the source register will clear the interrupt.
0x21: PULSE_CFG Register (Read/Write)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
DPA ELE ZDPEFE ZSPEFE YDPEFE YSPEFE XDPEFE XSPEFE
Table 36. PULSE_CFG Description
DPA
Double Pulse Abort. Default value: 0.
0: Double Pulse detection is not aborted if the start of a pulse is detected during the time period specified by the PULSE_LTCY register.
1: Setting the DPA bit momentarily suspends the double pulse detection if the start of a pulse is detected during the time period
specified by the PULSE_LTCY register and the pulse ends before the end of the time period specified by the PULSE_LTCY register.
ELE
Pulse event flags are latched into the PULSE_SRC register. Reading of the PULSE_SRC register clears the event flag.
Default value: 0.
0: Event flag latch disabled; 1: Event flag latch enabled
ZDPEFE
Event flag enable on double pulse event on Z-axis. Default value: 0.
0: Event detection disabled; 1: Event detection enabled
ZSPEFE
Event flag enable on single pulse event on Z-axis. Default value: 0.
0: Event detection disabled; 1: Event detection enabled
YDPEFE
Event flag enable on double pulse event on Y-axis. Default value: 0.
0: Event detection disabled; 1: Event detection enabled
YSPEFE
Event flag enable on single pulse event on Y-axis. Default value: 0.
0: Event detection disabled; 1: Event detection enabled
XDPEFE
Event flag enable on double pulse event on X-axis. Default value: 0.
0: Event detection disabled; 1: Event detection enabled
XSPEFE
Event flag enable on single pulse event on X-axis. Default value: 0.
0: Event detection disabled; 1: Event detection enabled
0x22: PULSE_SRC Register (Read Only)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
EA AxZ AxY AxX DPE PolZ PolY PolX
Table 37. PULSE_SRC Description
EA
Event Active Flag. Default value: 0.
(0: No interrupt has been generated; 1: One or more interrupt events have been generated)
AxZ
Z-axis event. Default value: 0.
(0: No interrupt; 1: Z-axis event has occurred)
AxY
Y-axis event. Default value: 0.
(0: No interrupt; 1: Y-axis event has occurred)
AxX
X-axis event. Default value: 0.
(0: No interrupt; 1: X-axis event has occurred)
DPE
Double pulse on first event. Default value: 0.
(0: Single Pulse Event triggered interrupt; 1: Double Pulse event triggered interrupt)
PolZ
Pulse polarity of Z-axis Event. Default value: 0.
(0: Pulse Event that triggered interrupt was Positive; 1: Pulse Event that triggered interrupt was negative)
PolY
Pulse polarity of Y-axis Event. Default value: 0.
(0: Pulse Event that triggered interrupt was Positive; 1: Pulse Event that triggered interrupt was negative)
PolX
Pulse polarity of X-axis Event. Default value: 0.
(0: Pulse Event that triggered interrupt was Positive; 1: Pulse Event that triggered interrupt was negative)