BS2824 Holtek Semiconductor Inc., BS2824 Datasheet - Page 43

• Manufacturer Part Number: BS2824
• Description: Touch Key Mcu
• Manufacturer: Holtek Semiconductor Inc.

Rev. 1.00
Reset Initial Conditions
Note:
The t
clock source is provided by ERC or HIRC. The SST is 1024 for HXT or LXT.
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 Idle/Sleep function or Watchdog Timer. The reset flags are shown in the
table:
Note: u 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.
The Watchdog time-out Reset during normal operation is the same as a hardware RES pin reset
except that the Watchdog time-out flag TO will be set to 1 .
The Watchdog time-out Reset during Idle/Sleep 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 t
details.
Watchdog Time-out Reset during Normal Operation
Watchdog Time-out Reset during Idle/Sleep mode
SST
can be chosen to be either 1024 or 2 clock cycles via configuration option if the system
Program Counter
Interrupts
WDT
Timer/Event Counter
Prescaler
Input/Output Ports
Stack Pointer
TO
0
u
1
1
WDT Time-out Reset during Normal Operation Timing Chart
PDF
0
u
u
1
Item
WDT Time-out Reset during Idle/Sleep Timing Chart
Note: t
Power-on reset
RES or LVR reset during Normal or Slow Mode operation
WDT time-out reset during Normal or Slow Mode operation
WDT time-out reset during Idle or Sleep Mode operation
RSTD
is power-on delay, typical time=100ms
Reset to zero
All interrupts will be disabled
Clear after reset, WDT begins counting
Timer Counter will be turned off
The Timer Counter Prescaler will be cleared
I/O ports will be setup as inputs
Stack Pointer will point to the top of the stack
43
BS2824/BS2854/BS2868
RESET Conditions
Condition After RESET
Touch Key MCU
January 27, 2010
SST