upd78f0114hgb-8es-a Renesas Electronics Corporation., upd78f0114hgb-8es-a Datasheet - Page 219

• Manufacturer Part Number: upd78f0114hgb-8es-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

10.4.3 Watchdog timer operation in STOP mode (when “internal oscillator can be stopped by software” is
system clock or internal oscillation clock is being used.
(1) When the CPU clock and the watchdog timer operation clock are the high-speed system clock (f
(2) When the CPU clock is the high-speed system clock (f
The watchdog timer stops counting during STOP instruction execution regardless of whether the high-speed
Figure 10-4. Operation in STOP Mode (CPU Clock and WDT Operation Clock: High-Speed System Clock)
the STOP instruction is executed
When the STOP instruction is executed, operation of the watchdog timer is stopped. After STOP mode is
released, counting stops for the oscillation stabilization time set by the oscillation stabilization time select register
(OSTS) and then counting is started again using the operation clock before the operation was stopped. At this
time, the counter is not cleared to 0 but holds its value.
internal oscillation clock (f
When the STOP instruction is executed, operation of the watchdog timer is stopped. After STOP mode is
released, counting is started again using the operation clock before the operation was stopped. At this time, the
counter is not cleared to 0 but holds its value.
Watchdog timer
Watchdog timer
CPU operation
CPU operation
selected by option byte)
(CPU Clock: High-Speed System Clock, WDT Operation Clock: Internal Oscillation Clock)
f
f
XP
XP
f
f
R
R
operation
Operating
operation
Operating Operation stopped
Normal
Normal
R
) when the STOP instruction is executed
Oscillation
Oscillation
stopped
stopped
STOP
STOP
Figure 10-5. Operation in STOP Mode
CHAPTER 10 WATCHDOG TIMER
User’s Manual U16961EJ4V0UD
Operation stopped
Oscillation stabilization time
Oscillation stabilization time
Oscillation stabilization time
Oscillation stabilization time
(set by OSTS register)
(set by OSTS register)
Operating
XP
) and the watchdog timer operation clock is the
Normal operation
Normal operation
Operating
XP
) when
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