¡ Semiconductor
MSM58321
¡ Semiconductor
MSM58321
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 microprocessor applications.
The time is read with 4-bit DATA I/O, ADDRESS WRITE, READ, and BUSY; it is written
with 4-bit DATA I/O, ADDRESS WRITE,
WRITE, and BUSY.
The 4-bit bidirectional bus line method is used
for the data I/O circuit; the clock is set, corrected, or read by accessing the memory.
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 VDD = 2.2V
Low power dissipation
90 µW max. at VDD = 3V
2.5 mW max. at VDD = 5V
• 16 pin plastic DIP (DIP 16-P-300)
FUNCTIONAL BLOCK DIAGRAM
5-poststage (O11~O15)
XT
RFB
215
1/60 Hz
1 Hz
1
OSC
XT
1024 Hz
1/3600 Hz
BUSY
R
R
BUSY
\DATA BUS
SWITCH
3
4
3
4
4
E-F
N
4
3
W
MI1 MI10
H1 H10
1/10 1/6
1/10 1/6
1/12 or 1/24
1/7
SECOND
MINUTE
HOUR
WEEK
S1 S10
STOP
S1 S10
MI1 MI10
H1 H10
TEST
Rp
TEST
1 Hz
D
Rp
WRITE
WRIETE
WRITE
Rp
W
READ
Rp
READ
CS1
Rp
DATA BUS
CS
TEST-P
CS2
Rp
4
D0
D1
D2
D3
ADDRESS
LATCH
ADDRESS
WRITE
Rp
4
Y1 Y10
1/12
1/10 1/10
DAY
CONTROL
4
MO1 MO10
1/10 1/3
TRI-STATE
MONTH
YEAR
D1 D10
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
4
4
WRITE
D1
D10
MO1 MO10
Y1
Y10
Rp = 200 k TYP
7
