HT1380_11 Datasheet, PDF (1/14 Pages) Holtek Semiconductor Inc – Serial Timekeeper Chip

HT1380/HT1381
Serial Timekeeper Chip
Features
· Operating voltage: 2.0V~5.5V
· Maximum input serial clock: 500kHz at V_DD=2V,
2MHz at V_DD=5V
· Operating current: less than 1mA at 2V,
less than 1.2mA at 5V
· TTL compatible
- V_IH: 2.0V~V_DD+0.3V at V_DD=5V
- V_IL: -0.3V~+0.8V at V_DD=5V
Applications
· Microcomputer serial clock
· Two data transmission modes: single-byte,
or burst mode
· Serial I/O transmission
· All registers store BCD format
· HT1380: 8-pin DIP package
HT1381: 8-pin SOP package
· Clock and Calendar
General Description
The HT1380/HT1381 is a serial timekeeper IC which
provides seconds, minutes, hours, day, date, month and
year information. The number of days in each month
and leap years are automatically adjusted. The
HT1380/HT1381 is designed for low power consump-
tion and can operate in two modes: one is the 12-hour
mode with an AM/PM indicator, the other is the 24-hour
mode.
The HT1380/HT1381 has several registers to store the
corresponding information with 8-bit data format. A
32768Hz crystal is required to provide the correct tim-
ing. In order to minimize the pin number, the
HT1380/HT1381 use a serial I/O transmission method
to interface with a microprocessor. Only three wires are
required: (1) REST, (2) SCLK and (3) I/O. Data can be
delivered 1 byte at a time or in a burst of up to 8 bytes.
Block Diagram
I/O
S C LK
D a ta S h ift
R e g is te r
R e a l T im e
C lo c k
REST
C om m and
C o n tr o l L o g ic
O s c illa to r a n d
X1
D iv id e r C ir c u it
X2
Pin Assignment
NC 1
X1 2
X2 3
VSS 4
8 VDD
7 S C LK
6 I/O
5 REST
H T1380
8 D IP -A
NC 1
X1 2
X2 3
VSS 4
8 VDD
7 S C LK
6 I/O
5 REST
H T1381
8 S O P -A
Rev. 1.30
1
May 27, 2011