¡ Semiconductor
MSM58321
¡ Semiconductor
REAL TIME CLOCK/CALENDAR
DESCRIPTION
The MSM 58321 is a metal gate CMOS Real
Time Clock/Calendar with a battery backup
function for use in bus-oriented micropro-
cessor applications.
The 4-bit bidirectional bus line method is used
for the data I/O circuit; the clock is set, cor-
rected, or read by accessing the memory.
MSM58321
The time is read with 4-bit DATA I/O, AD-
DRESS WRITE, READ, and
BUSY;
it is written
with 4-bit DATA I/O, ADDRESS WRITE,
WRITE, and
BUSY.
FEATURES
• 7 Function-Second, Minute, Hour, Day,
Day-of-Week, Month, Year
• Automatic leap year calender
• 12/24 hour format
• Frequency divider 5-poststage reset
• Reference signal output
•
•
•
•
32.768 kHz crystal controlled operation
Single 5V power supply
Back-up battery operation to V
DD
= 2.2V
Low power dissipation
90
µW
max. at V
DD
= 3V
2.5 mW max. at V
DD
= 5V
• 16 pin plastic DIP (DIP 16-P-300)
FUNCTIONAL BLOCK DIAGRAM
5-poststage (O
11
~O
15
)
XT
XT
BUSY
N
STOP
R
p
TEST
R
p
WRITE
R
p
READ
R
p
CS1
R
p
CS2
R
p
D0
D1
D2
D3
TRI-STATE
CONTROL
ADDRESS
LATCH
ADDRESS
DECODER
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E-F
S1
S10
MI1
MI10
H1
H10
W
D1
D10
MO1
MO10
Y1
Y10
D
E-F
1024 Hz
1 Hz
1/60 Hz
1/3600 Hz
\DATA BUS
4
E-F
4
SWITCH
S1 S10
1/10 1/6
3
4
MI1 MI10
1/10 1/6
MINUTE
3
H1 H10
1/12 or 1/24
W
1/7
WEEK
RFB
OSC
1
2
15
R
BUSY
R
4
3
TEST
D
WRIETE
1 Hz
WRITE
S1 S10
MI1 MI10
H1 H10
W
SECOND
HOUR
READ
CS
4
D1 D10
1/10 1/3
DAY
WRITE
D1
D10
MO1 MO10
Y1
Y10
DATA BUS
TEST-P
4
4
MO1 MO10
4
Y1 Y10
1/10 1/10
YEAR
4
1/12
MONTH
R
p
= 200 k TYP
ADDRESS
WRITE
R
p
7
OKI [ OKI ELECTRONIC COMPONETS ]
