HT56RB27 datasheet(90/153 Pages) HOLTEK

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· Watchdog Time-out Reset during Normal Operation

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

²1².

· Watchdog Time-out Reset during Power Down

The Watchdog time-out Reset during Power Down 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

²0² and the TO flag will be set to ²1². Refer to the A.C. Characteristics for t

SST details.

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 Power Down function or Watchdog Timer. The reset flags are shown in the table:

PDF

RESET Conditions

RES reset during power-on

RES or LVR reset during normal operation

WDT time-out reset during normal operation

WDT time-out reset during Power Down

Note:

²u² 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

Prescaler

The Timer Counter Prescaler will be cleared

Input/Output Ports

I/O ports will be setup as inputs

Stack Pointer

Stack Pointer will point to the top of the stack

Rev. 1.20

April 26, 2013

HT56RB27

TinyPowerTM A/D Type Smart Card OTP MCU

with DAC, ISO 7816 and USB Interfaces

W D T T i m e - o u t

S S T T i m e - o u t

C h i p R e s e t

t R S T D

WDT Time-out Reset during Normal Operation

Timing Chart

W D T T i m e - o u t

S S T T i m e - o u t

t S S T

WDT Time-out Reset during Power Down

Timing Chart

HT56RB27 数据表(PDF) 90 Page - Holtek Semiconductor Inc

HT56RB27 数据表(HTML) 90 Page - Holtek Semiconductor Inc

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