Epson RX8900SA/CE User Manual

ETM45E-01
Preliminary
Application Manual
Real Time Clock Module
RX8900SA/CE

Epson RX8900SA/CE Specifications

General

Model	RX8900SA/CE
Supply Voltage	1.6V to 5.5V
Interface	I2C-Bus
Operating Temperature	-40°C to +85°C
Type	Real Time Clock Module
Package	8-Pin MSOP

Summary

Application Manual

RX8900SA/CE Real Time Clock Module

Identifies the product as a real-time clock module and its model name.

1. Overview

2. Block Diagram

3. Terminal Description

3.1. Terminal Connections

Shows the physical pinouts for RX8900SA and RX8900CE models.

3.2. Pin Functions

Details the purpose and I/O for each pin of the RX8900 module.

4. Absolute Maximum Ratings

5. Recommended Operating Conditions

6. Frequency Characteristics

7. Electrical Characteristics

7.1. DC Characteristics

Details DC parameters like current consumption, input/output voltages, and leakage.

7.2. AC Characteristics

8. Use Methods

8.1. Description of Registers

Explains register access and provides tables for basic time/calendar registers.

8.1.3. Register Table (Extension Register)

8.2. Details of Registers

8.2.1. Clock Counter (SEC - HOUR)

Details the registers for seconds, minutes, and hours counters.

8.2.2. Calendar Counter (WEEK - YEAR)

8.2.3. Alarm Registers

8.2.4. Fixed-cycle Timer Control Registers

8.2.5. Extension Register

8.2.6. Flag Register

8.2.7. Control Register

1) CSEL0,1 (Compensation Interval Select 0, 1) bits

Sets the interval for temperature compensation operations.

2) UIE (Update Interrupt Enable) bit

Controls interrupt signal generation for time update events.

2) TIE (Timer Interrupt Enable) bit

3) AIE (Alarm Interrupt Enable) bit

8.2.8. Temperature Data Register

8.2.9. Backup Power Supply Function Register

8.3. Fixed-cycle Timer Interrupt Function

8.3.1. Diagram of Fixed-cycle Timer Interrupt Function

Illustrates the timing and signals involved in the fixed-cycle timer interrupt.

8.3.2. Related Registers and Timer Configuration

Timer Interrupt Intervals and Start Timing

8.4. Time Update Interrupt Function

8.4.1. Time Update Interrupt Function Diagram

Illustrates the timing and signals for the time update interrupt function.

8.4.2. Related Registers for Time Update Interrupt Functions

8.5. Alarm Interrupt Function

8.5.1. Diagram of Alarm Interrupt Function

Illustrates the timing and signals for the alarm interrupt function.

8.5.2. Related Registers

Alarm Setting Examples

8.6. Interrupt Function for /INT='L' Interrupt Output

8.7. Temperature Compensation Function

8.7.2. Related Registers for Temperature Compensation Function

Details registers (CSEL1, CSEL0) for setting the temperature compensation interval.

8.8. Battery Backup Switchover Function

8.8.1. Description of Battery Backup Switchover Function

Details the power-source detector and MOS switches for backup operation.

8.8.2. Control the Contents of the Power Switching

8.8.3. Function that can be used in the backup state

8.8.4. Notes on Power Switching Function

8.8.5. Related Registers of the Backup Power Supply Switching Function

8.9. Reading/Writing Data via the I2C Bus Interface

8.9.1. Overview of I2C-BUS

Provides a general overview of the I2C bus communication protocol.

8.9.2. System Configuration

Describes the system configuration for I2C bus connections.

8.9.3. Starting and Stopping I2C Bus Communications

8.9.4. Data Transfers and Acknowledge Responses during I2C-BUS Communications

8.9.5. Slave Address

8.9.6. I2C Bus Protocol

8.10. Backup and Recovery

8.11. Access at the Time of Backup Return and Initial Power Supply

8.12. Flow Chart

1) An Example of the Initialization

Details the steps for initializing the RX8900 module.

2) Method of Initialization after Starting of Internal Oscillation

3) The Setting of a Clock and Calendar

4) The Reading of a Clock and Calendar

8.13. Connection with Typical Microcontroller

8.14. When Used as a Clock Source (32 kHz-TCXO)

9. External Dimensions / Marking Layout

9.1. RX8900SA

Details physical dimensions and marking for the RX8900SA package.

9.2. RX8900CE

10. Application Notes

1) Notes on Handling

Offers precautions regarding static electricity, noise, and voltage levels.