upd78f0103hmca1-5a4-a Renesas Electronics Corporation., upd78f0103hmca1-5a4-a Datasheet - Page 180

• Manufacturer Part Number: upd78f0103hmca1-5a4-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

(4) When CPU clock and watchdog timer operation clock are the internal oscillation clocks (f
9.4.4
high-speed system clock (f
the high-speed system clock (f
again using the operation clock before the operation was stopped. At this time, the counter is not cleared to 0 but
holds its value.
180
The watchdog timer stops counting during HALT instruction execution regardless of whether the CPU clock is the
Figure 9-7. Operation in STOP Mode (CPU Clock and WDT Operation Clock: Internal Oscillation Clock)
CPU operation
instruction execution
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.
CPU operation
Watchdog timer
Watchdog timer
Watchdog timer operation in HALT mode (when “Internal oscillator can be stopped by software” is
selected by option byte)
f
f
XP
XP
f
f
(internal oscillation
Normal operation
R
R
Normal operation
Operating Operation stopped
Operating
clock)
XP
) or internal oscillation clock (f
XP
) or internal oscillation clock (f
Operation stopped
Oscillation
stopped
STOP
Figure 9-8. Operation in HALT Mode
HALT
CHAPTER 9 WATCHDOG TIMER
User’s Manual U16846EJ3V0UD
Clock supply stopped
Oscillation stabilization time
(set by OSTS register)
17 clocks
R
), or whether the operation clock of the watchdog timer is
Operating
R
). After HALT mode is released, counting is started
Normal operation (internal oscillation clock)
Normal operation
Operating
R
) during STOP