HT48R002 Datasheet, PDF (30/71 Pages) Holtek Semiconductor Inc – Cost-Effective I/O 8-Bit OTP MCU

HT48R002/HT48R003
Cost-Effective I/O 8-Bit OTP MCU
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 Mode function or Watchdog Timer. The reset flags are shown in the
table:
TO
PDF
RESET Conditions
0
0
Power-on reset
u
u
RES or LVR reset during NORMAL Mode operation
1
u
WDT time-out reset during NORMAL Mode operation
1
1
WDT time-out reset during Sleep Mode operation
Note: “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/Event Counter
Precaler
Input/Output Ports
Stack Pointer
Condition After RESET
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 set 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 the microcontroller internal registers.
Rev. 1.11
30
April 11, 2017