MMA8452Q
Sensors
10
Freescale Semiconductor, Inc.
4
System Modes (SYSMOD)
Figure 6. MMA8451Q Mode Transition Diagram
All register contents are preserved when transitioning from ACTIVE to STANDBY mode. Some registers are reset when
transitioning from STANDBY to ACTIVE. These are all noted in the device memory map register table. The SLEEP and WAKE
modes are ACTIVE modes. For more information on how to use the SLEEP and WAKE modes and how to transition between
these modes, please refer to the functionality section of this document.
Table 7. Mode of Operation Description
Mode
I
2
C Bus State
VDD
Function Description
OFF
Powered Down
< 1.8 V
VDDIO Can be > VDD
• The device is powered off.
• All analog and digital blocks are shutdown.
• I
2
C bus inhibited.
STANDBY
I
2
C communication is possible
> 1.8 V
• Only digital blocks are enabled.
Analog subsystem is disabled.
• Internal clocks disabled.
• Registers accessible for Read/Write.
• Device is configured in STANDBY mode.
ACTIVE
(WAKE/SLEEP)
I
2
C communication is possible
> 1.8 V
• All blocks are enabled (digital, analog).
OFF
WAKE
STANDBY
OFF
ACTIVE
SYSMOD = 00
SYSMOD = 10
SYSMOD = 01
Auto SLEEP/WAKE
Condition
VDD > 1.8 V
VDD < 1.8 V
CTRL_REG1
Active bit = 1
CTRL_REG1
Active bit = 0
CTRL_REG1
Active bit = 0
