Sony CXD5602 User Manual page 267

3.9.7.3.3 Excess Detection
The Excess Detection function performs excess detection to the value converted to 1 axis at the normalization
processing and then outputs an interrupt to the upper module. Also, the result of this conversion can be used for
writing control to the FIFO.
There are two thresholds in the internal comparator. The comparator determines whether the target input value
is bigger than top threshold or smaller than bottom threshold or not. Next to the comparator, two circuits are
connected in two-step cascade connection. They detect whether the "true" result of the comparator's
determination occurs for the specified number of times in series. The output from the second circuit becomes to be
the determination. By using registers, you can delay the interrupt occurrence which is output in response to the
determination.
The occurrence of the two interrupts: Rise interrupt which indicates the transition from Low to High, and Fall
interrupt which indicates the transition from High to Low, can be selected independently.
Figure SCU (Sensor Control Unit)-66 shows an example of the input value's change with time and the
operation of the excess detection.
dummy
UTHRESH
UCOUNT
LTHRESH
Status
DELAY_SAMPLE
Figure SCU (Sensor Control Unit)-66 Excess Detection Operation (by a Comparator and an Excess Detector)
The Excess Detection function of the MATH_PROC actually has a different interrupt output from the above
Figure because the excess detection is operated with two-step cascade connection.
Figure SCU (Sensor Control Unit)-67 shows the operation of excess detection in two-step cascade connection.
LCOUNT
over under
UTHRE LTHRES
SH H
Interrupt
over
UTHRESH
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CXD5602 User Manual