ULTRA-COMPACT
HIGH PERFORMANCE
SERIAL REAL-TIME CLOCK ICs
RS5C317A/B
ELECTRONIC DEVICES DIVISION
NO.EA-036-9908
APPLICATION MANUAL
NOTICE
1. The products and the product specifications described in this application manual are subject to change or dis-
continuation of production without notice for reasons such as improvement. Therefore, before deciding to use
the products, please refer to Ricoh sales representatives for the latest information thereon.
2. This application manual may not be copied or otherwise reproduced in whole or in part without prior written con-
sent of Ricoh.
3. Please be sure to take any necessary formalities under relevant laws or regulations before exporting or other-
wise taking out of your country the products or the technical information described herein.
4. The technical information described in this application manual shows typical characteristics of and example
application circuits for the products. The release of such information is not to be construed as a warranty of or a
grant of license under Ricoh's or any third party's intellectual property rights or any other rights.
5. The products listed in this document are intended and designed for use as general electronic components in
standard applications (office equipment, computer equipment, measuring instruments, consumer electronic
products, amusement equipment etc.). Those customers intending to use a product in an application requiring
extreme quality and reliability, for example, in a highly specific application where the failure or misoperation of
the product could result in human injury or death (aircraft, spacevehicle, nuclear reactor control system, traffic
control system, automotive and transportation equipment, combustion equipment, safety devices, life support
system etc.) should first contact us.
6. We are making our continuous effort to improve the quality and reliability of our products, but semiconductor
products are likely to fail with certain probability. In order prevent any injury to persons or damages to property
resulting from such failure, customers should be careful enough to incorporate safety measures in their design,
such as redundancy feature, fire-containment feature and fail-safe feature. We do not assume any liability or
responsibility for any loss or damage arising from misuse or inappropriate use of the products.
7. Anti-radiation design is not implemented in the products described in this application manual.
8. Please contact Ricoh sales representatives should you have any questions or comments concerning the prod-
ucts or the technical information.
June 1995
OUTLINE
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1
FEATURES
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1
BLOCK DIAGRAM
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2
APPLICATIONS
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2
PIN CONFIGURATION
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2
PIN DESCRIPTIONS
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3
ABSOLUTE MAXIMUM RATINGS
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4
RECOMMENDED OPERATING CONDITIONS
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4
DC CHARACTERISTICS
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5
AC CHARACTERISTICS
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5
TIMING CHARTS
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6
FUNCTIONAL DESCRIPTIONS
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7
1. Addressing
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7
2. Registers
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8
3. Counters
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14
USAGES
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16
1. Read Data (For the RS5C317A)
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16
2. Write Data (For the RS5C317A)
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17
3. Read Data (For the RS5C317B)
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18
4. Write Data (For the RS5C317B)
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19
5. CE Pin
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20
6. Configuration of Oscillating Circuit
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21
7. Oscillator Halt Sensing
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22
8. Typical Power Supply Circuit
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23
9. Oscillation Frequency Adjustment
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23
10. Interrupt Operation
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25
RS5C317A/B
APPLICATION MANUAL
CONTENTS
11. Timer
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27
12. 32kHz Clock Output
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27
13. Typical Application
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28
14. Typical Characteristic Measurements
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29
15. Typical Software-based Operations
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31
PACKAGE DIMENSIONS
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35
TAPING SPECIFICATION
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35
ULTRA-COMPACT HIGH PERFORMANCE
SERIAL REAL-TIME CLOCK ICs
1
RS5C317A/B
OUTLINE
The RS5C317A/B are CMOS type real-time clock ICs which are connected to the CPU via three signal lines and
capable of serial transmission of clock and calendar data to the CPU.
The RS5C317A/B can generate various periodic interrupt clock pulses lasting for long period (one month), further
alarm interrupt can be made by days of the week, hours, and minutes. The function of 32kHz clock output and timer
counter for watch-dog-timer are also include. Driving an oscillation circuit at constant voltage, the circuit undergoes
few voltage fluctuations and consequently realizes low current consumption (0.6A at 3V). It also provides an oscil-
lator halt sensing function for application to data validity at power-on and other occasions. Integrated into a compact
and thin 14pin SSOP (0.65mm pitch), the RS5C317A/B are the optimum choice for equipment requiring small size
and low power consumption.
The RS5C317A and the RS5C317B reads/writes data at falling and rising edge of serial clock respectively.
Time keeping voltage 1.6V to 6.0V
Lowest supply current 0.6A TYP. (1.5A MAX.) at 3V
Connection to the CPU via only three pins: CE, SCLK/SCLK and SIO for addressing and data read/write
A clock counter (counting hours, minutes, and seconds) and a calendar counter (counting leap years, years,
months, days, and days of the week) in BCD code
Periodic interrupt pulses to the CPU with cycles ranging from one month to 1/1024Hz, with interrupt flags and
interrupt halt
Alarm interrupt (days of the week, hours, minutes)
Counter for timer with internal clock
Oscillator halt sensing to judge internal data validity
32kHz clock output with enable switch
Second digit adjustment by 30 seconds
12-hour or 24-hour time display selectable
Automatic leap year recognition up to the year 2099
CMOS logic
Package: 14pin SSOP (0.65mm pitch)
FEATURES
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