HT82K94E datasheet(17/43 Pages) HOLTEK

17 / 43 page

HT82K94E/HT82K94A

Rev. 1.50

October 11, 2007

optioned as CMOS/NMOS/PMOS configurations.

These control registers are mapped to locations 13H,

15H, 17H and 19H.

After a chip reset, these input/output lines remain at high

levels or floating state (depending on the pull-high op-

tions). Each bit of these input/output latches can be set

or cleared by

²SET [m].i² and ²CLR [m].i² (m=12H, 14H,

16H or 18H) instructions.

Some instructions first input data and then follow the

output operations. For example,

²SET [m].i², ²CLR

[m].i

², ²CPL [m]², ²CPLA [m]² read the entire port states

into the CPU, execute the defined operations

(bit-operation), and then write the results back to the

latches or the accumulator.

Each line of all the I/O ports have the capability of wak-

ing up the device.

There are pull-high options available for I/O lines. Once

the pull-high option of an I/O line is selected, the I/O line

have pull-high resistor. Otherwise, the pull-high resistor

is absent. It should be noted that a non-pull-high I/O line

operating in input mode will cause a floating state.

It is recommended that unused or not bonded out I/O

lines should be set as output pins by software instruction

to avoid consuming power under input floating state.

Low Voltage Reset/Detector

- LVR/LVD

The microcontroller contains a low voltage reset circuit

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

supply voltage of the device drops to within a range of

0.9V~VLVR such as might occur when changing the bat-

tery, the LVR will automatically reset the device inter-

nally.

The LVR includes the following specifications:

· For a valid LVR signal, a low voltage i.e. a voltage in

the range between 0.9V~VLVR must exist for greater

than 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.

Note:

VOPR is the voltage range for proper chip opera-

tion at 4MHz system clock.

There is a low voltage detector (LVD) and a low voltage

reset circuit (LVR) implemented in the microcontrollers.

Where LVR function can be enabled/disabled by op-

tions. User can read the LVD detector status (0/1) from

MISC.5. The LVR has the same effect or function with

the external RES signal which performs a chip reset.

Both LVR and LVD functions will disable in the HALT

mode.

There are two kind of LVR/LVD definition: 2-battery or

3-battery option.

When 2-battery option is selected: LVR=2.2V;

LVD=2.4V. Otherwise, 3-battery option is selected:

LVR=2.4V; LVD=2.6V.

5 . 5 V

2 . 2 V ~ 2 . 4 V

2 . 0 V ~ 2 . 2 V

0 . 9 V

V D D

V O P R

V L V R

5 . 5 V

V D D

5 . 5 V

V L V R

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 low voltage has to be maintained for over 1ms in its original state, therefore there

¢s a 1ms delay

before entering the reset mode

HT82K94E датащи(PDF) 17 Page - Holtek Semiconductor Inc

HT82K94E датащи(HTML) 17 Page - Holtek Semiconductor Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

датащи скачать

ссылки URL