Fujitsu FR81S User Manual
CHAPTER 19: BASE TIMER
5. Operation
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER
: BASE TIMER
FUJITSU SEMICONDUCTOR CONFIDENTIAL
90
Notes:
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If a detection of measurement end edge and a timer reactivation occur simultaneously, the following
may result. In such case, set the interrupt control correctly by considering the operation of interrupt
request flag.
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Single measurement mode: The timer reactivates and waits for a measurement start edge. Also, the
EDIR bit (the measurement end interrupt request flag) of the status control register (BTxSTC) is set to
"1".
⋅
Continuous measurement mode: The timer reactivates and waits for a measurement start edge. Also, the
EDIR bit (the measurement end interrupt request flag) of the status control register (BTxSTC) is set to
"1". Also, the current measurement result is transferred to the data buffer register (BTxDTBF).
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If the 16/32-bit PWC timer is reactivated in the continuous measurement mode and if a measurement
start edge is detected in the input signal (TIN) simultaneously, the timer immediately starts counting
from the value "0001H".
Calculating the Pulse Width
After the measurement, the measurement result can be read from the base timer x data buffer register
(BTxDTBF) and the measured pulse width can be calculated using the following formula.
Pulse width = n × T
n: Data buffer register (BTxDTBF) value
T: Count clock cycle
MB91520 Series
MN705-00010-1v0-E
723