LSI LS 1357
4 Digit Time With Colon Default
Timer
Version 1.2 (24, 10, 2003)
1. Features
4 digit LCD display with two dots.
Default Timer for Hour / Minute or Day / Hour by bonding option.
1 keys operation.
4 bonding option to select default timer value.
Very low power consumption.
32768 Crystal oscillator.
Single 1.5V operation.
��� Direct drive 1/2 bias 1/3 duty LCD(Vop 3.0V).
Alarm sound: The alarm sound continues for 60 seconds. It generates (4KHz x
4Hz x 1Hz) sound signal at first 60 seconds. The alarm sound will be stopped by
pressing any key.
Key tone : It will generate a sound signal (tone) when start/stop key is pressed.
Power on : All LCD segments and the alarm sound are turned on for two second.
LCD Drawing
LSI LS 1357
Version 1.2(24, 10, 2003)
2
Operation Flow
(a) After the power on, it return to display shows “Default timer value”, “colon”
and “TM” always on (not flash).
(b) Countdown Timer: This timer fixed timing count down. The step is one
minute or one day (selectable by bonding option) . Press “Start/Stop” key to
start counting. The “TM” always on. The “colon” 0.5 second on and 0.5
second off at counting, no flash at stop The alarm sound generates when the
timer reached zero, press “Start/Stop” key to stop counting even the timer in
counting or reached zero, press the key again then return to continues
counting.
(c) Press “Start/Stop” and hold it for 2 second, the timer will reload “Default
timer value” and stand-by for start counting.
(d) Keys: Only “ST/SP” key for start, stop and repeat.
Pin Assignment
DESIGNATION TYPE DESCRIPTION
B0, B1 OUTPUT Buzzer output
V1, V2 OUTPUT Doubler output
VEE OUTPUT -1.5V
T1, T2 INPUT TEST pin
OO OUTPUT 32KHz oscillator output
OI INPUT 32KHz oscillator input
VDD POWER +1.5V power supply
GND POWER Ground
I0, I1, I2, I3, I4 and I5 INPUT(PL) Input key
C[1:3] OUTPUT LCD Common output
S[1:10] OUTPUT LCD Segment output
PB INPUT(PH) RESET
O0, O1, O2 and O3 OUTPUT Output Pin
Note: (PH) - pull high , (PL) – pull low.
Absolute Maximum Ratings
Supply voltage Vdd - Vss..........................0 to 5V
Input voltage Vin.................................Vss to Vdd
Operating temperature Top .............-10°C to 60°C
Storing temperature Tst ...................-40°C to 70°C
Comments
Stress above those listed under Absolute Maximum Ratings may
cause permanent damage to the device. These are stress rating
only. Functional operation of this device at these or any other
conditions above those indicated in the operational sections of
this specification is not implied and exposure to absolute maximum
rating conditions for extended periods may affect device
reliability.
D.C. Electrical Characteristics