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A.9 Period Measurement with Missing Transition Detection (PMM)
Period measurement with missing transition detect (PMM) allows a special-purpose
23-bit period measurement. It detects the occurrence of a missing transition (caused
by a missing tooth on the sensed wheel), indicated by a period measurement that is
greater than a programmable ratio of the previous period measurement. Once detected, this condition can be counted and compared to a programmable number of additional transitions detected before TCR2 is reset to $FFFF. In addition, one byte at an
address specified by a channel parameter can be read and used as a flag. A non-zero
value of the flag indicates that TCR2 is to be reset to $FFFF once the next missing
transition is detected.
Figure A-7 shows the host interface areas and parameter RAM for the PMM function.
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