Fujitsu FR81S 사용자 설명서
CHAPTER 20: RELOAD TIMER
5. Operation
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : RELOAD TIMER
FUJITSU SEMICONDUCTOR CONFIDENTIAL
FUJITSU SEMICONDUCTOR CONFIDENTIAL
37
5.3.3. Dual One-shot Operation
The dual one-shot operation is shown below.
When bit15, bit14:MOD[1:0] of the TMCSR register =01, and bit4:RELD of the TMCSR register =0, the
timer performs the dual one-shot operation. This can be used as a one-shot PPG.
timer performs the dual one-shot operation. This can be used as a one-shot PPG.
In dual one-shot operation, values are loaded into the counter one by one in the order of TMRLRA then
TMRLRB, the loaded values decrements the counter for each load. The counter will stop by the second
underflow.
TMRLRB, the loaded values decrements the counter for each load. The counter will stop by the second
underflow.
When bit5:OUTL=0 of the TMCSR register, the value of TMRLRA represents the time interval between a
timer activation (TOUT output is in L level) to a toggling of the TOUT output to "H", and the value of
TMRLRB represents the time interval of H width of the TOUT output.
timer activation (TOUT output is in L level) to a toggling of the TOUT output to "H", and the value of
TMRLRB represents the time interval of H width of the TOUT output.
Figure 5-9 TOUT Pulse Width
When the first underflow occurs (UF-A), the following operation will take place.
⋅ Sets bit2:UF bit of the TMCSR register.
⋅ When interrupts are enabled (bit3:INTE=1 of TMCSR register), an interrupt occurs.
⋅ Loads TMRLRB to the counter.
⋅ Inverts TOUT output.
⋅ Starts a down count from TMRLRB.
⋅ Loads TMRLRB to the counter.
⋅ Inverts TOUT output.
⋅ Starts a down count from TMRLRB.
When the second underflow (UF-B) occurs, the following operation will take place.
⋅ Sets bit2:UF bit of the TMCSR register.
⋅ When interrupts are enabled (bit3:INTE=1 of TMCSR register), an interrupt occurs.
⋅ When interrupts are enabled (bit3:INTE=1 of TMCSR register), an interrupt occurs.
⋅ Stops the count with 0xFFFF.
⋅ Initializes TOUT output.
⋅ Timer is waiting for an activation trigger.
⋅ Initializes TOUT output.
⋅ Timer is waiting for an activation trigger.
Trigger
TOUT external pin output
↓
Delay = TMRLRA
H width = TMRLRB
MB91520 Series
MN705-00010-1v0-E
764