KXTI9-1001 Datasheet, PDF (48/54 Pages) List of Unclassifed Manufacturers – 2g/4g/8g Tri-axis Digital Accelerometer Specifications

± 2g / 4g / 8g Tri-axis Digital
Accelerometer Specifications
PART NUMBER:
KXTI9-1001
Rev. 2
Jul-2011
Trigger Mode
Data Accumulation
When a physical interrupt is caused by one of the digital engines, the trigger
event is asserted and SMP[6:0] samples prior to the event are retained. Sample
collection continues until the buffer is full.
Data Reporting
Data is reported with the oldest sample first (uses FIFO read pointer).
Status Indicators
When a physical interrupt occurs and there are at least SMP[6:0] samples in the
buffer, BUF_TRIG in BUF_STATUS_REG2 is asserted.
FILO Mode
Data Accumulation
Sample collection continues when the buffer is full; older data is discarded to
make room for newer data.
Data Reporting
Data is reported with the newest byte of the newest sample first (Z_H or Z based
on resolution).
Status Indicators
A watermark interrupt occurs when the number of samples in the buffer
reaches the Sample Threshold. The watermark interrupt stays active until the
buffer contains less than this number of samples. This can be accomplished
through clearing the buffer or explicitly reading greater than SMPX samples
(calculated with Equation 1).
Buffer Operation
The following diagrams illustrate the operation of the buffer conceptually. Actual physical
implementation has been abstracted to offer a simplified explanation of how the different buffer
modes operate. Figure 9 represents a high-resolution 3-axis sample within the buffer. Figures
10-18 represent a 10-sample version of the buffer (for simplicity), with Sample Threshold set to
8.
Regardless of the selected mode, the buffer fills sequentially, one byte at a time. Figure 9
shows one 6-byte data sample. Note the location of the FILO read pointer versus that of the
FIFO read pointer.
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