Watchdog Time-out Reset during SLEEP or IDLE Mode
The Watchdog time-out Reset during SLEEP or IDLE Mode is a little different from other kinds of
reset. Most of the conditions remain unchanged except that the Program Counter and the Stack Pointer
will be cleared to
²
0
²
and the TO flag will be set to
²
1
²
. Refer to the A.C. Characteristics for t
SST
details.
Note:
The t
SST
is 15~16 clock cycles if the system clock source is provided by HIRC. The t
SST
is 1~2 clock for
LIRC.
Reset Initial Conditions
The different types of reset described affect the reset flags in different ways. These flags, known as
PDF and TO are located in the status register and are controlled by various microcontroller operations,
such as the SLEEP or IDLE Mode function or Watchdog Timer. The reset flags are shown in the table:
TO
RESET Conditions
0
0
Power-on reset
u
u
RES or LVR reset during NORMAL or SLOW Mode operation
1
u
WDT time-out reset during NORMAL or SLOW Mode operation
1
1
WDT time-out reset during IDLE or SLEEP Mode operation
Note:
²
u
²
stands for unchanged
The following table indicates the way in which the various components of the microcontroller are af-
fected after a power-on reset occurs.
Item
Condition After RESET
Program Counter
Reset to zero
Interrupts
All interrupts will be disabled
WDT
Clear after reset, WDT begins counting
Timer/Event Counter
Timer Counter will be turned off
Input/Output Ports
I/O ports will be setup as inputs
Stack Pointer
Stack Pointer will point to the top of the stack
Rev. 1.50
50
April 28, 2020
BS83B08-3/B12-3/B16-3/B16G-3/C24-3
8-Bit Touch Key Flash MCU
t
S S T
W D T T i m e - o u t
I n t e r n a l R e s e t
WDT Time-out Reset during SLEEP or IDLE Timing Chart