HT6750A Просмотр технического описания (PDF) - Holtek Semiconductor

Номер в каталоге

Компоненты Описание

производитель

HT6750A

Date Printer

Holtek Semiconductor 

HT6750A

Functional Description

· 6-digit timer in 5 modes: Mode selection for 3 key

applications

· Date from 1-1-²98 to 31-12-²49 (2049) automatic

updating, including leap years.

· Matrix address LCD interface in 1/3 duty, 1/2 bias,

frame frequency is 43Hz.

· Printing enable is ²Go low² trigger in X input. VXÜ1/2

VDD, Debounce in printing trigger: 1ms£TDEBOUNCE£2ms.

· After printing, ²¾² will blink 3 times at 1Hz rate.

· Print means lamp output ²LOW² to light lamp. Lamp

output sink current is 40mA Min. (Constant current

source ), typical 45mA (VDD=2.4V~5.5V).

· Printing time: 30ms, 45ms, 60ms or programmable

(determined by the control CPU of the camera), se-

lected by D or T and Topt inputs.

· Built-in crystal (32768Hz) oscillator circuit (capacitor

and resistor).

· At ²OFF² mode ( - - - - - - ), printing (Lamp on) and

data setting is inhibited in any case and printing ²¾²

mark OFF.

M

'Y M D

D H :M

A s ia n C a le n d a r D a y , H o u r , M in u te

O ..

M

M D 'Y

M

D M 'Y

A m e r ic a n C a le n d a r E u r o p e a n C a le n d a r

· Default value at power on is ² ¢98 1 1² (ASIAN DATE ).

· Date and time cannot be set with printing ²¾² mark

ON.

· LCD segment test pin is provided, a ²SEGON² is

pull-low which will force all segments ON. This test pin

is normally pull-high through an on chip 1kW resistor.

· ²:² mark is still at time mode, at time setting, ²digit² se-

lected by SEL pin will blink at 1Hz and 1/2 duty rate.

· At setting mode (SET), printing ²¾² mark is OFF and

printing is inhibited.

· The selected digit (blinking) count up by one at short

intervals (1.0sec£TSET£1.25sec), when the ON key is

pressed for less than 1.0sec; if the SET key is pressed

longer than 1.25sec, the digit will count up rapidly at

8Hz rate.

· Printing is disabled during data and time setting.

TON

T O ..

Debounce time of MODE, SEL, SET key is:

ON recognition: when the ON key is pressed longer

than TON, ON is recognized.

31.25ms£TON£62.5ms,

OFF recognition: when the ON key is pressed longer

than TOFF , OFF is recognized; the next input has to

wait.

31.25ms£TOFF£62.5ms,

· If at least one key-ON time pulse is detected during

the ²TOFF² period, the time before the key-ON pulse is

regarded as the key-ON time.

The lamp light-up time is controlled depending on the

levels of D and T pins.

D

T Lamp signal output time

H

H 60ms

H

L 30ms

L

H Depend on X input pulse width

L

L 45ms

· ²X² pin must be carefully protected, the system cannot

be reset when in ±200V and 200pF one-shot test.

(add external resistor 10kW series with the pad; it¢s

better if it works well without the resistor)

· At ²OFF² mode, no data can be set.

· The X input is rejected in some condition, such as:

¨ OFF mode

¨ Selection and Setting mode (In these condition the

lamp must be turned off)

· Power on reset and after crystal is stable (max. 2 sec)

· Regulator output voltage accuracy is 2V±3.0% (after

TRIM)

· Display in Day-Hour-Minute mode, in 24-hour system

(0~23)

Operation flowchart

M

'9 8 1 1

1 0 :00

A s ia n C a le n d a r D a y , H o u r , M in u te

O ..

M

1 1 '9 8

M

1 1 '9 8

M

'9 8 1 1

A m e r ic a n C a le n d a r E u r o p e a n C a le n d a r A s ia n C a le n d a r

Mode selection sequence and initial value: (²MODE²

key)

In digit setting, press the ²SET² key

· The digit selected will blink at a 1hz rate.

· The blinking digit (selected digit) will count up by itself.

· If ²SET² key is pressed ³1sec, the digit will count up

rapidly at an 8Hz rate, otherwise count up by 1 every

time it¢s pressed (£1sec).

· When the colon (²:²) is blinking in the

Day-Hour-Minute mode, pressing the SET key will re-

set the seconds to 00.

Rev. 1.00

5

January 17, 2003

Share Link: