AN4650 datasheet(19/102 Pages) STMICROELECTRONICS

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AN4650

Operating modes

102

2.1

Power-Down mode

When the accelerometer/gyroscope is in Power-Down mode, almost all internal blocks of

the device are switched off to minimize power consumption. Digital interfaces (I2C and SPI)

are still active to allow communication with the device. The content of the configuration

registers is preserved and the output data registers are not updated, keeping the last data

sampled in memory before going into Power-Down mode.

2.2

High-Performance mode

In High-Performance mode, all accelerometer/gyroscope circuitry is always on and data are

generated at the data rate selected through the ODR_XL/ODR_G bits.

Data interrupt generation is active.

2.3

Normal mode

While High-Performance mode guarantees the best performance in terms of noise, Normal

mode further reduces the current consumption. The accelerometer/gyroscope data reading

chain is automatically turned on and off to save power. In the gyroscope device, only the

driving circuitry is always on.

Data interrupt generation is active.

2.4

Low-Power mode

Low-Power mode differs from Normal mode in the available output data rates. In Low-Power

mode low-speed ODRs are enabled; three low-speed ODRs can be chosen through the

ODR_XL/ODR_G bits: 13 Hz, 26 Hz and 52 Hz.

Data interrupt generation is active.

2.5

Gyroscope Sleep mode

While the gyroscope is in Sleep mode the circuitry that drives the oscillation of the

gyroscope mass is kept active. Compared to gyroscope Power-Down, turn-on time from

Sleep mode to Low-Power/Normal/High-Performance mode is drastically reduced.

If the gyroscope is not configured in Power-Down mode, it enters in Sleep mode when the

Sleep mode enable (SLEEP_G) bit of CTRL4_C register is set to 1, regardless of the

selected gyroscope ODR.

AN4650 Datasheet(PDF) 19 Page - STMicroelectronics