PCF1171CU datasheet(4/16 Pages) PHILIPS

4 / 16 page

1997 Apr 16

Philips Semiconductors

Product speciﬁcation

4-digit LCD car clock

PCF1171C

Fig.2 Segment designation of LCD.

MSA984

P1 (P3)

P2 (P4)

Fig.3 Display mode (24-hour mode shown).

MSA985

TIME

OPERATIONAL INPUTS

Operational inputs S1, S2 and S3 have an internal pull-up

resistor to facilitate use of external single-pole,

single-throw switches. A specific debounce circuit is

integrated as protection against contact debounce and

parasitic voltages.

In the description below, an arrangement as shown in

Fig.5 is assumed and S1, S2 and S3 refer to the external

switches rather than the corresponding inputs.

Set hours, switch S1

Closure of S1 increments the hours according to the

correction mode selected by S6 (see Chapter

“Input options”).

Set minutes/reset seconds, switch S2

When S2 is closed, the minute setting is corrected

according to the correction mode determined by S6 (see

Chapter “Input options”).

The seconds counter is reset to zero each time S2 is

closed, and begins running each time S2 is opened.

Segment test/reset, switches S1 and S2

If S1 and S2 are closed simultaneously all LCD segments

are switched on. When the switches are released, the

clock starts at 1 : 00 in the 12-hour mode or 0 : 00 in the

24-hour mode.

PCF1171CU Datasheet(PDF) 4 Page - NXP Semiconductors