Fujitsu F2MC-16LX Hardware Manual page 307

I Restart
Restart is defined as a start operation (setting the STRT bit to "0") performed after entering
timer/pulse width measurement mode.
Restart operates as follows depending on the mode:
❍ One-shot timer mode
Restart has no effect.
❍ Reload Timer Mode
Reload is performed and operation continues. If a restart occurs at the same time as an
overflow, the overflow flag (OVIR) is set.
❍ Pulse width measurement mode
In the measurement start edge wait state, restart has an effect. In measurement mode, counting
stops and the measurement start edge wait state is entered. If, in this mode, measurement end
edge detection and restart occur at the same time, the measurement end flag (EDIR) is set. In
repeated measurement mode, the result will be transferred to the PWCR.
I Stop
In one-shot timer mode or one-shot measurement mode, no explicit stop operation needs to be
performed because counting will automatically stop at a timer overflow or at measurement end.
However, in other modes, the timer must be forcibly stopped. Moreover, providing an explicit
stop operation allows the timer to stop before it would stop automatically.
❍ Comparing and selection of two inputs
If a forcible stop is performed before the edge selected via PWC1 has been detected, the first
measurement result after restart of measurement will contain an error. Be sure to perform a
forcible stop only after the PWC1 edge has been detected.
I Confirmation of operation state
The STRT/STOP bits, which have been explained above, operate as operation state indicator
bits when read.
Table 14.3-4 Function of the operation state indicator bits
STRT
0
1
Note:
The same value is returned regardless of whether STRT or STOP bit is read. If these bits are
read with read-modify-write instructions (such as bit operation instructions), 11
returned. Do not use read-modify-write instructions for reading.
STOP
Timer stop (except in measurement start edge wait state):
0 Indicates that the timer has not started or that measurement
has ended.
Timer counting is being performed or the system is in
1
measurement start edge wait state
CHAPTER 14 PWC TIMER
Operation state
is always
B
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