I3G4250D Datasheet, PDF (17/43 Pages) STMicroelectronics – 3-axis digital output gyroscope

I3G4250D
Main digital blocks
3.2.1
Bypass mode
In Bypass mode, the FIFO is not operational and for this reason it remains empty. As
illustrated in Figure 7, only the first address is used for each channel. The remaining FIFO
slots are empty. When new data is available, the old data is overwritten.
Figure 7. Bypass mode
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3.2.2
FIFO mode
In FIFO mode, data from the yaw, pitch, and roll channels are stored in the FIFO. A
watermark interrupt can be enabled (I2_WMK bit in CTRL_REG3 (22h)), which is triggered
when the FIFO is filled to the level specified by the WTM 4:0 bits of FIFO_CTRL_REG
(2Eh). The FIFO continues filling until it is full (32 slots of 16-bit data for yaw, pitch, and roll).
When full, the FIFO stops collecting data from the input channels. To restart data collection,
it is necessary to write FIFO_CTRL_REG (2Eh) back to Bypass mode.
FIFO mode is represented in Figure 8.
Figure 8. FIFO mode
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DocID027628 Rev 2
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