HT48R062 Ver la hoja de datos (PDF) - Holtek Semiconductor

Número de pieza

componentes Descripción

Fabricante

HT48R062

Cost-Effective I/O Type 8-Bit MCU

Holtek Semiconductor 

HT48R062/HT48C062

Low Voltage Reset - LVR

The microcontroller provides low voltage reset circuit in

order to monitor the supply voltage of the device. If the

supply voltage of the device is within the range

0.9V~VLVR, such as changing a battery, the LVR will au-

tomatically reset the device internally.

The LVR includes the following specifications:

· The low voltage (0.9V~VLVR) has to remain in their

original state to exceed 1ms. If the low voltage state

does not exceed 1ms, the LVR will ignore it and do not

perform a reset function.

· The LVR uses the ²OR² function with the external

RES signal to perform chip reset.

The relationship between VDD and VLVR is shown below.

V DD

V O PR

5 .5 V 5 .5 V

V LV R

3 .0 V

2 .2 V

Note:

0 .9 V

VOPR is the voltage range for proper chip opera-

tion at 4MHz system clock.

V DD

5 .5 V

V LV R

0 .9 V

0V

R e s e t S ig n a l

L V R D e te c t V o lta g e

R eset

N o r m a l O p e r a tio n

R eset

*1

*2

Low Voltage Reset

Note:

*1: To make sure that the system oscillator has stabilized, the SST provides an extra delay of 1024 system

clock pulses before entering the normal operation.

*2: Since low voltage has to be maintained in its original state and exceed 1ms, therefore 1ms delay enters

the reset mode.

Options

The following table shows eight kinds of code option in the HT48R062/HT48C062. All the code options must be defined

to ensure proper system functioning.

No.

Options

1

WDT clock source: WDTOSC or fSYS/4

2

WDT function: enable or disable

3

LVR function: enable or disable

4

CLRWDT instruction(s): one or two clear WDT instruction(s)

5

System oscillator: RC or crystal

6

PA and PB pull-high resistors: none or pull-high

7

PA0~PA7 wake-up: enable or disable

Rev. 1.21

11

December 30, 2008

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