Fujitsu FR81S User Manual
CHAPTER 27: UP/DOWN COUNTER
6. Operation and Setting Procedure Examples
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : UP/DOWN COUNTER
FUJITSU SEMICONDUCTOR CONFIDENTIAL
FUJITSU SEMICONDUCTOR CONFIDENTIAL
28
Operation performed when the reload function is in use
The operation is similar to that in timer mode. See "
■ Counting" in "6.1. Operation in Timer Mode".
Operation performed when the compare function is in use
When the up/down counter value matches the value set in the reload compare register (RCR), the CMPF bit
of the counter status register (CSR) changes to "1". At this time, a compare result match interrupt request
occurs if the CITE bit of the counter status register (CSR) is set to "1".
of the counter status register (CSR) changes to "1". At this time, a compare result match interrupt request
occurs if the CITE bit of the counter status register (CSR) is set to "1".
If an attempt is made to further increment the counter in this condition, the up/down counter value is cleared
to "0000
to "0000
H
" and counting-up restarts.
Figure 6-4 shows the operation performed when the compare function is in use.
Figure 6-4 Operation Performed When the Compare Function is in Use
Note:
If the compare function is in use, the up/down counter value will be cleared to "0000
H
" when one of the
following conditions is fulfilled.
· The up/down counter value matches the value set in the reload compare register (RCR) (compare result
match) and further, the next counting up operation is performed.
· However, a comparison result match does not cause clearing of the up/down counter value if one of the
following conditions is fulfilled:
· The next operation is counting down.
· The up/down counter is inactive.
· The up/down counter is inactive.
RCR
RCR : Reload compare register
Compare result
match
match
00
H
FF
H
(0FFFF
H
)
Counter clear
(Compare result match interrupt
request generation)
Compare result
match
match
Counter clear
(Compare result match interrupt
request generation)
MB91520 Series
MN705-00010-1v0-E
1035