KXTI9-1001 Datasheet, PDF (47/54 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
Sample Buffer Feature Description
The sample buffer feature of the KXTI9 accumulates and outputs acceleration data based on how it is
configured. There are 4 buffer modes available, and samples can be accumulated at either low (8-bit) or high
(12-bit) resolution. Acceleration data is collected at the ODR specified by OSAA:OSAD in the Output Data
Control Register. Each buffer mode accumulates data, reports data, and interacts with status indicators in a
slightly different way.
FIFO Mode
Data Accumulation
Sample collection stops when the buffer is full.
Data Reporting
Data is reported with the oldest byte of the oldest sample first (X_L or X 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 6).
BUF_RES=0:
SMPX = SMP_LEV[7:0] / 3 – SMP_TH[6:0]
BUF_RES=1:
SMPX = SMP_LEV[7:0] / 6 – SMP_TH[6:0]
Equation 6. Samples Above Sample Threshold
Stream 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 oldest sample first (uses FIFO read pointer).
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).
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