ULTRA-COMPACT SERIAL
ALARM REAL TIME CLOCK
RS5C316A/B
APPLICATION MANUAL
ELECTRONIC DEVICES DIVISION
NO.EA-035-9803
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
RS5C316A/B
APPLICATION MANUAL
CONTENTS
......................................................................................................
1
FEATURES
....................................................................................................
1
BLOCK DIAGRAMS
.......................................................................................
2
APPLICATIONS
.............................................................................................
2
SELECTION GUIDE
.......................................................................................
2
PIN CONFIGURATION
...................................................................................
2
PIN DESCRIPTIONS
......................................................................................
3
ABSOLUTE MAXIMUM RATINGS
...................................................................
4
RECOMMENDED OPERATING CONDITIONS
.................................................
4
DC CHARACTERISTICS
................................................................................
5
AC CHARACTERISTICS
................................................................................
5
TIMING CHART
.............................................................................................
6
FUNCTIONAL DESCRIPTION
.........................................................................
7
1. Addressing
.................................................................................................
7
2. Registers
...................................................................................................
8
3. Counters
..................................................................................................
13
OPERATION
................................................................................................
15
1. Read Data (For the RS5C316A)
......................................................................
15
2. Write Data (For the RS5C316A)
.......................................................................
16
3. Read Data (For the RS5C316B)
......................................................................
17
4. Write Data (For the RS5C316B)
.......................................................................
18
5. CE Pin
....................................................................................................
19
6. Configuration of Oscillating Circuit
....................................................................
20
7. Oscillator Halt Sensing
.................................................................................
21
8. Typical Power Supply Circuit
...........................................................................
22
9. Oscillation Frequency Adjustment
.....................................................................
22
OUTLINE
....................................................................................
24
11. Typical Application
.....................................................................................
26
12. Typical Characteristic Measurements
...............................................................
27
13. Typical Software-based Operations
.................................................................
29
PACKAGE DIMENSION
................................................................................
33
TAPING SPECIFICATION
..............................................................................
33
10. Interrupt Operation
URTRA-COMPACT SERIAL ALARM REAL
TIME CLOCK
RS5C316A/B
OUTLINE
The RS5C316A/B is a CMOS type real-time clock which is connected to the CPU via three signal lines and capa-
ble of serial transmission of clock and calendar data to the CPU.
The RS5C316A/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. Driving an oscillation circuit at constant volt-
age, the circuit undergoes few voltage fluctuations and consequently realizes low current consumption (0.6µA at
3V). It also provides an oscillator halt sensing function for application to data validity at power-on and other occa-
sions. Integrated into an ultra compact and ultra thin 8pin SSOP (0.65mm pitch), the RS5C316A/B is the optimum
choice for equipment requiring small size and low power consumption.
The RS5C316A and the RS5C316B reads/writes data at falling and rising edge of serial clock respectively.
FEATURES
• Time keeping voltage 1.6V to 6.0V
• Lowest supply current 0.6µA TYP. (1.5µA 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)
• Oscillator halt sensing to judge internal data validity
• 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: 8pin SSOP (0.65mm pitch)
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