BS83B08A-3 Datasheet, PDF (50/119 Pages) Holtek Semiconductor Inc – 8-Bit Touch Key Flash MCU

BS83B08A-3/BS83B12A-3/BS83B16A-3
BS83B08A-4/BS83B12A-4/BS83B16A-4
8-Bit Touch Key Flash MCU
• Watchdog Time-out Reset during Normal Operation
The Watchdog time-out Reset during normal operation is the same as a LVR reset except that the
Watchdog time-out flag TO will be set to “1”.
Note: tRSTD is power-on delay, typical time=16.7ms
WDT Time-out Reset during Normal Operation Timing Chart
• 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 “0” and the TO flag will be set to “1”. Refer to the A.C. Characteristics
for tSST details.
Note: The tSST is 15~16 clock cycles if the system clock source is provided by the HIRC.
The tSST is 1~2 clock for the LIRC.
WDT Time-out Reset during SLEEP or IDLE Timing Chart
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
PDF
RESET Conditions
0
0
Power-on reset
u
u
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
“u” stands for unchanged
The following table indicates the way in which the various components of the microcontroller are
affected after a power-on reset occurs.
Item
Program Counter
Interrupts
WDT
Timer/Eventer Counter
Input/Output Ports
Stack Pointer
Condition After RESET
Reset to zero
All interrupts will be disabled
Clear after reset, WDT begins counting
Timer/Eventer Counter will be turned off
I/O ports will be setup as inputs
Stack Pointer will point to the top of the stack
The different kinds of resets all affect the internal registers of the microcontroller in different ways.
To ensure reliable continuation of normal program execution after a reset occurs, it is important to
know what condition the microcontroller is in after a particular reset occurs. The following table
describes how each type of reset affects each of the microcontroller internal registers.
Rev. 1.00
50
May 02, 2013