NEC 78K0 User Manual page 210

Table 10-2. Mask Option Setting and Watchdog Timer Operation Mode
Watchdog timer clock
source
Operation after reset
Operation mode selection
Features
Notes 1. As long as power is being supplied, Ring-OSC oscillation cannot be stopped (except in the reset
period).
2. The conditions under which clock supply to the watchdog timer is stopped differ depending on
the clock source of the watchdog timer.
<1> If the clock source is f
<2> If the clock source is f
Remarks 1. f : Ring-OSC clock oscillation frequency
R
2. f : X1 input clock oscillation frequency
XP
210
CHAPTER 10 WATCHDOG TIMER
Ring-OSC Cannot Be Stopped
Note 1
Fixed to f .
R
Operation starts with the maximum
18
interval (f /2 ).
R
The interval can be changed only
once.
The watchdog timer cannot be
stopped.
, clock supply to the watchdog timer is stopped under the following
XP
conditions.
• When f
is stopped
XP
• In HALT/STOP mode
• During oscillation stabilization time
, clock supply to the watchdog timer is stopped under the following
R
conditions.
• If the CPU clock is f
and if f
XP
instruction
• In HALT/STOP mode
User's Manual U16227EJ2V0UD
Mask Option
Ring-OSC Can Be Stopped by Software
• Selectable by software (f
stopped)
• When reset is released: f
Operation starts with the maximum
18
interval (f /2 ).
R
The clock selection/interval can be
changed only once.
The watchdog timer can be stopped in
Note 2
standby mode
is stopped by software before execution of the STOP
R
, f or
XP R
R
.