REAL-TIME CLOCK
WITH INTERNAL RAM
RP/RF5C01A
NO. EK-086-9804
OUTLINE
The RP/RF5C01A are real-time clocks for microcomputers that can be connected directly to buses of microcom-
puters with such CPUs as the 8085A or Z80 and allow setting or reading of the clock with the same procedures as
for the Read/Write operation for memory.
These products have various features such as clock and calendar counters, alarm functions, and 26
´
4bits RAM
which can be backed up by batteries. They can then be used as non-volatile RAM.
FEATURES
• Connected directly to CPU
• 4bit bidirectional data bus : D0 - D3
• 4bit address input : A0 - A3
• Built-in clock counter (hour, minute, second) and calendar counter (leap year, year, month, day, day-of-the-week)
• Supports both 12-hour AM/PM clock and 24-hour clock
• All clock data expressed in BCD codes
• Backed up by batteries (minimum:2.2V)
• ±30 second adjustment function
• Built-in 26
´
4bits RAM
• Outputs alarm signals or timing pulse of 16Hz or 1Hz.
• Packages : 18pin DIP (RP5C01A) ; 18pin SOP(RF5C01A)
BLOCK DIAGRAM
1H
z
,16H
z
,
OSCIN
OSCOUT
S
2
S
3
S
4
S
5
S
6
S
7
S
8
OSC
1/2
15
4
T-RESET
RD.WR.
MODE01
A-RESET
3
4
2
3
4
2
ALARM REGISTER
ADJ
CS
CS
RD
WR
ADJ
HOLD
CLOCK
HOLD
RD. WR.
MODE 00
COMPARATOR
ALARM
ALARM
ALARM
OUTPUT
SECONDS MINUTES
1
1
1
1
1
HOURS
1
DAYS
1
MONTHS
1
YEARS
1
/
10
/
6
/
10
/
6
/
12
/
24
/
7
1
/
28
- /
31
1
/
12
/
10 1
/
10 1
/
4
RD.WR.
MODE10,MODE11
SO-SC
26
´
4bits
RAM
S0
4 3
S1 S2 S3 S4 S5 S6 S7 S8 S9 SA SB SC
4 3 4 2 3 4 2 4 1 4 4 2
4
4
CONTROLLER
SD
-SF
SO
SF
ADDRESS
DECODER
BUS
CONTROL
INTERNAL
BUS
BUFFER
A
0
A
1
A
2
A
3
D
0
D
1
D
2
D
3
LEAP
YEARS
WEEK
1
RICOH [ RICOH ELECTRONICS DEVICES DIVISION ]
