I3G4250D Datasheet, PDF (18/43 Pages) STMicroelectronics – 3-axis digital output gyroscope

Main digital blocks
I3G4250D
3.2.3
Stream mode
In Stream mode, data from yaw, pitch, and roll measurements are stored in the FIFO. A
watermark interrupt can be enabled and set as in FIFO mode. The FIFO continues filling
until full (32 slots of 16-bit data for yaw, pitch, and roll). When full, the FIFO discards the
older data as the new data arrives. Programmable watermark level events can be enabled
to generate dedicated interrupts on the DRDY/INT2 pin (configured through CTRL_REG3
(22h)).
Stream mode is represented in Figure 9.
Figure 9. Stream mode
[_L\_L]_L
[_
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[_
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[_
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[_
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[_
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3.2.4
Retrieving data from FIFO
FIFO data is read from the OUT_X, OUT_Y, and OUT_Z registers. When the FIFO is in
Stream, Bypass or FIFO mode, a read operation to the OUT_X, OUT_Y or OUT_Z registers
provides the data stored in the FIFO. Each time data is read from the FIFO, the oldest pitch,
roll, and yaw data are placed in the OUT_X, OUT_Y and OUT_Z registers, and both single
read and read-burst (X, Y & Z with auto-incremental address) operations can be used. In
read-burst mode, when data included in OUT_Z_H is read, the system again starts to read
information from OUT_X_L.
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