Fujitsu MB91460 SERIES FR60 User Manual page 869

5.6 Clear Timing
(1) When a clear request (Compare-match, ZIN edge detection and writing "0" to the clear bit UDCLR) is
made, clear is performed next time when Up/Down Counter counts up.
0066
Compare value
0065
Count value
Clear request
Countup
Clear timing
(2) Even if a clear request (Compare-match, ZIN edge detection and writing "0" to the clear bit DCC) is made,
clear is not performed when UP/Down Counter counts neither up nor down.
0066
Compare value
0065
Count value
Clear request
Countup
Countdown
Clear timing (None)
(3) If Up/Down Counter does not count up after a clear request (Compare-match, ZIN edge detection and
writing "0" to the clear bit DCC) is made, the counter is cleared when counting is disabled (CSTR="0").
Compare value
Count value
Clear request
Countup
CSTR or ZIN gate function
(4) When Up/Down Counter exceeds the maximum count, the overflow flag is set to "1" and the counter value
is returned to "0000".
Count value
Countup
Overflow
H
0066
H
H H
0066
H
0066
H
0065
H
FFFEH FFFEH
0000
H H
0065
H H
0066
H
FFFFH FFFFH
Chapter 41 Up/Down Counter
0001
H
0000
H
0000 0000
H
5.Operation
853