REAL-TIME CLOCK
RP/RF/RJ5C15
OUTLINE
NO. EK-086-9908
The RP/RF/RJ5C15 are real-time clocks for microcomputers that can be connected directly to data buses of
16bit CPUs, such as the 8086, Z8000, and 68000, and of 8bit CPUs, such as the 8085A, Z80, 6809, and 6502. They
allow setting or reading of the clock with the same procedures as for the Read/Write operation for memory.
These products have various features including clock, calendar and alarm functions and can be backed up by
batteries.
FEATURES
• Connected directly to CPU enabling fast access.
• 4bit address input : A0 - A3
• All clock data expressed in BCD codes
• Backed up by batteries (minimum : 2.0V)
• 4bit bidirectional data bus : D0 - D3
• Built-in clock counter (hour, minute, second) and calendar counter (leap year, year, month, day, day-of-the-week)
• Selectable basic clock frequency : 16kHz, 1kHz, 128Hz, 16Hz, 1Hz, 1/60Hz.
• Outputs alarm signals or timing pulse of 16Hz or 1Hz.
• Supply voltage : Single power supply of +5V
• Packages RP5C15......18pin DIP
RF5C15......18pin SOP
RJ5C15......28pin PLCC
• CMOS technology
BLOCK DIAGRAM
OSCIN
OSCOUT
OSC
O
N
1/2
15
16
k
H
z
, 1
k
H
z
, 128H
z
, 16H
z
, 1H
z
, 1/60H
z
S
2
S
3
S
4
S
5
S
6
S
7
S
8
TI
4
2
3
4
2
COMPARATOR
HOURS
WEEK
DAYS
1
4
3
IS
C
T.RESET
RD.WR.
BANK 1
ALARM
RESET
RD. WR.
ALARM REGISTER
ALARM
ALARM
BANK 0. RD. WR.
LEAP
YEARS
CS
CS
CLOCK
HOLD
SECONDS MINUTES
1
RD
/
10 1
/
6 1
/
10 1
/
6 1
/
12 1
/
24 1
/
7
/
28
-
1
/
31
WR
D
ADJ
HOLD
S1 S2 S3 S4 S5 S6 S7 S8 S9 SA SB SC
4 S0 3 4 3 4 2 3 4 2 4 1 4 4 2
3
4
CONTROLLER
SD
-SF
SO
SF
ADDRESS
DECODER
BUS
CONTROL
A
0
A
1
A
2
A
3
D
0
D
1
D
2
D
3
N
U
ED
1H
z
, 16H
z
ALARM
OUTPUT
MONTHS
1
YEARS
1
/
12
/
10 1
/
10 1
/
4
CLKOUT
CLOCK
SELECT
CLOCK
OUTPUT
1
RICOH [ RICOH ELECTRONICS DEVICES DIVISION ]
