Fujitsu FR81S 사용자 설명서
CHAPTER 19: BASE TIMER
5. Operation
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER
: BASE TIMER
FUJITSU SEMICONDUCTOR CONFIDENTIAL
65
5.5.3. Operation in One-Shot Mode
This section explains the operation in one-shot mode.
This section explains the operation in one-shot mode.
Counting Operation
In this mode, counting stops if an underflow occurs when the value of the 16-bit down counter changes from
the value set in the cycle setting register (BTxPCSR) to "FFFF
H
".
To use this mode, set one-shot mode by setting the MDSE bit of the timer control register (BTxTMCR) to
"1"(MDSE=1).
Activation
It is the same operation as in reload mode. See "Operation" in the section entitled "5.5.2 Operation in
Reload Mode".
Counting Operation
When an activation trigger is input, the 16-bit down counter, in synchronization with the count clock, starts
decreasing from the value set in the cycle setting register (BTxPCSR). When the value of the 16-bit down
counter matches the value of the duty setting register (BTxPDUT), the operation is performed as follows:
⋅
The DTIR bit of the base timer x status control register (BTxSTC) changes to "1".
⋅
The level of the output signal (TOUT signal) is inverted.
⋅
Countdown is continued. Later, when the 16-bit down counter underflows, the operation is performed as
follows:
⋅
The UDIR bit of the base timer x status control register (BTxSTC) changes to "1".
⋅
The level of the output signal (TOUT signal) is inverted.
⋅
Counting stops (The 16-bit down counter stops at the value "FFFF
H
").
Operation to be performed when an activation trigger is input during counting depends on whether
reactivation is permitted based on the RTGEN bit of the timer control register (BTxTMCR).
⋅
If reactivation is not permitted (RTGEN = 0):Any activation trigger is ignored when it is entered during
counting.
⋅
If reactivation is permitted (RTGEN = 1): The TGIR bit of the base timer x status control register
(BTxSTC) changes to "1". In addition, the value set in the
base timer x cycle setting register (BTxPCSR) is reloaded to
the 16-bit down counter, which begins counting.
MB91520 Series
MN705-00010-1v0-E
698