HT46R46/HT46C46/HT46R47/HT46C47

Rev. 1.00

21

December 28, 2004

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~3.3V, such as changing a battery, the LVR will au-

tomatically reset the device internally.

The LVR includes the following specifications:

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.

²OR² function with the external RES

signal to perform chip reset.

Note:

operation at 4MHz system clock.

5 . 5 V

3 . 0 V

2 . 2 V

0 . 9 V

5 . 5 V

5 . 5 V

0 . 9 V

0 V

R e s e t S i g n a l

R e s e t

* 1

* 2

N o r m a l O p e r a t i o n

R e s e t

L V R D e t e c t V o l t a g e

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 the low voltage has to maintain in its original state and exceed 1ms, therefore 1ms delay enter the

reset mode.

Options

The following table shows all kinds of options in the microcontroller. All of the options must be defined to ensure proper

system functioning.

No.

Options

1

2

WDT function: enable or disable

3

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

4

System oscillator: RC or crystal

5

Pull-high resistors (PA, PB, PD): none or pull-high

6

PWM enable or disable

7

PA0~PA7 wake-up: enable or disable

8

PFD enable or disable

9

Low voltage reset selection: enable or disable LVR function.