PCF1174CT Philips Semiconductors, PCF1174CT Datasheet - Page 6

• Manufacturer Part Number: PCF1174CT
• Description: 4-digit static LCD car clock
• Manufacturer: Philips Semiconductors

Philips Semiconductors
12/24-hour mode
Operation in 12-hour or 24-hour mode is selected by
connecting MODE to V
Power-on
After connecting the supply, the start-up mode is:
1:00 AM; 12-hour mode.
0:00; 24-hour mode.
Colon
If FLASH is connected to V
If FLASH is connected to V
Time setting
Switch inputs S1 and S2 have a pull-up resistor to facilitate
the use of single-pole, single-throw contacts. A debounce
circuit is incorporated to protect against contact bounce
and parasitic voltages.
Set enable
Inputs S1 and S2 are enabled by connecting ENABLE to
V
Set hours
When S1 is connected to V
advances by one and after one second continues with one
advance per second until S1 is released (auto-increment).
Set minutes
When S2 is connected to V
minutes advances by one and after one second continues
with one advance per second until S2 is released
(auto-increment). In addition to minute correction, the
seconds counter is reset to zero.
1997 Apr 16
DD
4-digit static LCD car clock
or disabled by connecting to V
DD
or V
DD
SS
SS
SS
the colon is static.
the hours displayed
the time displayed in
SS
the colon pulses at 1 Hz.
respectively.
SS
.
6
Segment test/reset
When S1 and S2 are connected to V
are switched ON. Releasing switches S1 and S2 resets the
display. No reset occurs when DATA is connected to V
(overlapping S1 and S2).
Test mode
When TS is connected to V
operating mode. When connecting TS to V
(seconds, minutes and hours) are stopped, allowing quick
testing of the display via S1 and S2 (debounce and
auto-increment times are 64 times faster). TS has a
pull-up resistor but for reasons of safety it should be
connected to V
EEPROM
V
be connected to V
LCD voltage programming
To enable LCD voltage programming, SEL is set to
open-circuit and a level of V
(see Fig.6). The first pulse (t
clears the EEPROM to give the lowest voltage output.
Further pulses (t
steps of typically 150 mV (T
For programming, measure V
pulse (t
maximum number of steps (n = 31) is reached and an
additional pulse is applied the voltage will return to the
lowest value.
Time calibration
To compensate for the tolerance in the quartz crystal
frequency which has been positively offset (nominal
deviation +60
and output, a number (n) of 262144 Hz pulses are
inhibited every second of operation.
PP
has a pull-up resistor but for reasons of safety it should
W
) when the required value is reached. If the
DD
10
L
) will increment the output voltage by
.
DD
6
) by capacitors at the oscillator input
.
DD
amb
DD
E
) applied to the DATA input
DD
, the device is in normal
= 25 C).
5 V is applied to V
V
SS
SS
Product specification
, all LCD segments
PCF1174C
and apply a store
SS
all counters
PP
SS