Epson RX8804CE Applications Manual
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Epson RX8804CE Applications Manual

Real time clock module
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ETM59E-05
l
Application Manua
Real Time Clock Module
RX8804CE
Preliminary

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Summary of Contents for Epson RX8804CE

  • Page 1 ETM59E-05 Application Manua Real Time Clock Module RX8804CE Preliminary...
  • Page 2 Epson’s official web sites and resources. 2. This document may not be copied, reproduced, or used for any other purposes, in whole or in part, without Epson’s prior consent. 3. Information provided in this document including, but not limited to application circuits, programs and usage, is for reference purpose only.
  • Page 3 ETM59E Revision History Rev No. Date Page Description Release ETM59E-01 16.Apr.2018 Updated Pull-up Resistor value. Updated mention of tCD. 18.Apr.2018 EVIN connects to VDD of 32kHz-TCXO. Note of Timing chart. I2C bus time out is 1second(Max,) from 2seconds, Peak Current consumption (2) 50µA(Typ.) from 55µA(Typ.) 8.2.5.

  • Page 4: Table Of Contents

    RX8804CE Table of Contents 1. Overview..............................1 2. Block Diagram ............................1 3. Terminal Description ..........................2 3.1. Terminal Connections ............................2 3.2. Pin Functions ................................. 2 4. Absolute Maximum Ratings ........................3 5. Recommended Operating Conditions ...................... 3 6. Frequency Characteristics ........................3 7.
  • Page 5 RX8804CE 8.14. When Used as a Clock Source (32 kHz-TCXO) ....................42 9. External Dimensions / Marking Layout....................43 9.1. RX8804CE ................................43 9.1.1. External Dimensions ..........................43 9.1.2. Marking Layout ............................43 10.Application Notes ..........................44 11.Figures ..............................45 12.Tables ..............................

  • Page 6: Overview

    RX8804CE C-Bus Interface Real-time Clock Module RX8804 • Built-in 32.768 kHz DTCXO • Interface Type C-Bus (Up to 400 kHz) • Low current consumption at backup : 350 nA / 3.0 V Typ. • Wide time-keeping voltage range : 1.5 V to 5.5 V •...

  • Page 7: Terminal Description

    RX8804CE 3. Terminal Description 3.1. Terminal Connections RX8804CE 1. FOE 10. /INT 2. V 9. GND 3. EVIN 8. T2 4. FOUT 7. SDA 5. SCL 6. SOUT Figure 2 Pin Layout 3.2. Pin Functions Table 1 Pin Functions Signal...

  • Page 8: Absolute Maximum Ratings

    RX8804CE 4. Absolute Maximum Ratings Table 2 Absolute Maximum Rating GND = 0 V Item Symbol Condition Rating Unit −0.3 to +6.5 Supply voltage Between V and GND GND −0.3 to +6.5 Input voltage (1) FOE, SCL, SDA, EVIN pins GND −0.3 to V...

  • Page 9: Electrical Characteristics

    RX8804CE *6 The result that it was measured at 25 C, 24 hours after processing of reflow soldering. 7. Electrical Characteristics 7.1. DC Characteristics Table 5 DC Characteristics = 1.5 V to 5.5 V, Ta = −40 C to +105 C...

  • Page 10: Ac Characteristics

    RX8804CE 7.2. AC Characteristics Table 6 AC Characteristics = 1.6 V to 5.5 V , Ta = −40 C to +105 C * Unless otherwise specified, GND = 0 V , V SCL = 100 kHz SCL = 400 kHz...

  • Page 11: Reference Characteristics

    7.3. Reference Characteristics 7.3.1 Temperature Compensation and Consumption Current The current consumption of RX8804CE increases at a timing of a temperature compensation. As for this peak current consumption, it occurs in about 0.7ms. is the average current consumption at temperature compensation in 2 seconds cycle.

  • Page 12: Use Methods

    RX8804CE 8. Use Methods 8.1. Description of Registers 8.1.1. Write / Read and Bank Select Address 00h to 0Fh: Basic time and calendar register. It compatible with RX8803 and RX8900 Address 10h to 1Fh: Extension register Access to more than address 20h is possible, but there is some control register for quality inspection.

  • Page 13: Register Table (Time Stamp, Evin, Sout, Timer)

    RX8804CE 8.1.3. Register Table (Time stamp, EVIN, SOUT, Timer) Table 10 Register Table (10h ~ 1Fh) Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 Init Write −  Time stamp SEC −...

  • Page 14: Clock Counter (Sec - Year)

    RX8804CE 8.2. Details of Registers 8.2.1. Clock Counter (SEC - YEAR) •The data format is BCD format. For example, when the “seconds” register value is “0101 1001” it indicates 59 seconds. 24hours system is available. Table 13 Clock, Calendar Register...

  • Page 15: Alarm Registers

    RX8804CE 3) MONTH register This MONTH register counts from 01 (January), 02 (February), and up to 12 (December), then starts again since 01 (January). 4) YEAR register This YEAR register counts from 00, 01, 02 and up to 99, then starts again since 00.

  • Page 16: Wakeup Timer Control Registers

    RX8804CE 8.2.3. Wakeup Timer Control Registers Table 17 Wakeup Timer Control Registers Read Write Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0   Timer Counter 0   Timer Counter 1...

  • Page 17: Table 21 Vdet Bit

    RX8804CE 3) VDET (Voltage Detection Flag) bit This flag bit indicates the history of the voltage for temperature compensation circuit. Its value changes from “0” to “1” indicates that the temperature compensation function has stopped operation due to a supply voltage drop. Once this flag bit's value is 1, its value is retained until a 0 is written to it.

  • Page 18: Sout Control Register

    RX8804CE 7) FSEL0, 1 (FOUT frequency Select 0, 1) bits The combination of these two bits is used to set the FOUT frequency. Note: All frequencies are temperature compensated! Table 23 FSEL bit FSEL1 FSEL0 FSEL0,1 FOUT frequency (bit 3) (bit 2) 32.768 kHz Output...

  • Page 19: Time Stamp Data Event Controller Register

    RX8804CE Table 26 DCE, DC bit SOUT output Flag value decided by SRV, FS2, FS1, FS0 SOUT = Low, SRV bit is ignored SOUT = High, SRV bit is ignored 3) SRV bit (SOUT Reverse) SOUT output reverse. Each Flag register is high active. In case of SRV = 1, IT becomes low active.

  • Page 20: Table 30 Ecp Bit

    RX8804CE 1) Time stamp SEC ~ YEAR In case of trigger input detection from EVIN terminal, Clock and calendar data are recorded in Time stamp SEC ~ YEAR. 2) TSVLF, TSVDET bit (Time stamp VLF, Time stamp VDET) In case of trigger input detection from EVIN terminal, VLF bit is recorded to TSVLF, VDET bit to TSVDET.

  • Page 21: Table 35 Et Bit

    RX8804CE 8) ET1, ET0 bit (Event input debounce Time set) Selection of debounce filtering cycle time. Table 35 ET bit Filtering Cycle Time ET0, 1 Write / Read No filtered * Default 3.9 ms 15.6 ms 125 ms *In case of no filtering, larger than 60 s active input is detected.

  • Page 22: Sout Function

    RX8804CE 8.3. SOUT Function 8.3.1. Various Function of SOUT The flag value selected by FS bit can be outputted at SOUT pin. See SOUT Function program ex.1 By this function RTC inner self monitoring flag VDET, VLF are outputted at SOUT pin despite /INT pin.

  • Page 23: Sout Function Program Ex.2

    RX8804CE SOUT Function Program ex.2 8.3.3. By setting DC bit, SOUT pin can control status like a general OUT put port. Timing chart SOUT Function program are described step 9 ~ E. Program ex.2 1.0 V Typ. VLF Flag Hi-Z...

  • Page 24: Evin Interrupt And Time Stamp Function

    RX8804CE 8.4. EVIN Interrupt and Time Stamp Function At the EVIN input timing, the time data, VDET and VLF date are stored to registers. An application ex. User can obtain the timing information ex. System error timing and analyses. 8.4.1. Time Stamp Program ex.

  • Page 25: Timing Chart Of Evin Time Stamping

    RX8804CE 8.4.2. Timing Chart of EVIN Time Stamping " 1 " " 1 " EIE bit " 0 " Hi-Z /INT output " L " " 1 " EF bit " 0 " Event occurs RTC internal operation Write operation Figure 11 EVIN Timing Chart (1) An EVIN interrupt event occurred.

  • Page 26: Alarm Interrupt Function

    RX8804CE 8.5. Alarm Interrupt Function 8.5.1. Alarm Interrupt Function The alarm interrupt function generates interrupt events at the matching time of alarm day, hour, and minute settings. When an interrupt event occurs, the AF bit value is set to “1” and the /INT pin goes to low level to indicate that an event has occurred.

  • Page 27: Examples Of Alarm Settings

    RX8804CE AF (Alarm Flag) bit When this flag bit value is already set to “0”, occurrence of an alarm interrupt event changes it to “1”. When this flag bit value is “1”, its value is retained until a “0” is written to it.

  • Page 28: Alarm Interrupt Timing Chart

    RX8804CE 2) Example of Alarm Settings when Day has been Specified (and WADA bit = ”1”) Table 43 Alarm Setting ex.2 Reg - A Reg - 9 Reg - 8 Day is specified HOUR Alarm Alarm WADA bit = 1 •...

  • Page 29: Int Pin Operation When An Interrupt Occurs

    RX8804CE 8.5.5. /INT pin Operation when an Interrupt Occurs. How to identify events when the interrupt output occurs /INT output pin is common output terminal of interrupt events of four types Wakeup timer, alarm, time update and EVIN interrupt. When an interrupt occurs, please read the TF, AF, UF and EF flag to confirm which types of events occurred.

  • Page 30: Table 45 Tesl Bit

    RX8804CE 1) TSEL0, 1bits (Timer Select 0, 1) The combination of these two bits is used to set the countdown period source clock for the wakeup timer interrupt function (four settings can be made). Table 45 TESL bit Auto reset time...

  • Page 31: Wakeup Timer Start Timing

    RX8804CE 4) TE (Timer Enable) bit This bit controls the start/stop setting for the wakeup timer interrupt function. Table 48 TE bit Data Description Preset value loaded to all Timer counter, and count-down stops Starts wakeup timer countdown Write / Read ...

  • Page 32: Wakeup Timer Interrupt Interval (Example)

    RX8804CE 8.3.4. Wakeup Timer Interrupt Interval (example) Table 51 Wakeup Timer Interrupt Interval Source clock Preset Value 4096 Hz 64 Hz "Second" update "Minute" update TSEL1,0 = 0,0 TSEL1,0 = 0,1 TSEL1,0 = 1,0 TSEL1,0 = 1,1 − − −...
  • Page 33 RX8804CE When a “1” is written to the TE bit, the wakeup timer countdown starts from the preset value. A wakeup timer interrupt event starts a countdown based on the countdown period (source clock). When the count value changes from 01h to 00h, an interrupt event occurs.

  • Page 34: Time Update Interrupt Function

    RX8804CE 8.7. Time Update Interrupt Function 8.7.1. Time Update Interrupt Function The time update interrupt function generates interrupt events at one-second or one-minute intervals, according to the timing of the internal clock. When an interrupt event occurs, the UF bit value becomes “1” and the /INT pin goes to low level to indicate that an event has occurred.

  • Page 35: Time Update Interrupt Function Timing Chart

    RX8804CE When a time update interrupt event occurs (UF bit value changes from “0” to ”1”), this bit selects whether to generate an interrupt signal (/INT status changes from Hi-Z to low) or to not generate it (/INT status remains Hi-Z).

  • Page 36: Temperature Compensation Function

    RX8804CE 8.8. Temperature Compensation Function 8.8.1. Temperature Compensation Function During the production process of the RTC, we are programming the individual characteristics of the built-in crystal into the non-volatile memory of the RTC. The build-in temperature sensor measures the actual temperature of the module and compensates the oscillation frequency of the crystal oscillator using the stored compensation data.

  • Page 37: Reading / Writing Data Via The I

    RX8804CE 8.9. Reading / Writing Data via the I C-Bus Interface 8.9.1. Overview of I C-Bus The I C-Bus supports bi-directional communications via two signal lines: the SDA (data) line and SCL (clock) line. A combination of these two signals is used to transmit and receive communication start/stop signals, data transfer signals, acknowledge signals, and so on.

  • Page 38: Starting And Stopping I C-Bus Communications

    RX8804CE 8.9.3. Starting and stopping I C-Bus communications START Repeated START (RESTART) STOP condition condition condition [ S ] [ Sr ] [ P ] 1 s Max. Figure 21 I C-Bus Start Stop Timing Cart 1) START condition, repeated START condition, and STOP condition (1) START condition The SDA level changes from high to low while SCL is at high level.

  • Page 39: Data Transfers And Acknowledge Responses During I C-Bus Communications

    RX8804CE 8.9.4. Data Transfers and Acknowledge Responses during I C-Bus Communications 1) Data transfers Data transfers are performed in 8-bit (1 byte) units once the START condition has occurred. There is no limit on the amount (bytes) of data that are transferred between the START condition and STOP condition.

  • Page 40: Slave Address

    RX8804CE 8.9.5. Slave Address The I C-Bus device does not include a chip select pin such as is found in ordinary logic devices. Instead of using a chip select pin, slave addresses are allocated to each device. All communications begin with transmitting the [START condition] + [slave address (+ R/W specification)]. The receiving device responds to this communication only when the specified slave address it has received matches its own slave address.

  • Page 41: I 2 C-Bus Protocol

    8.9.6. I C-Bus Protocol In the following sequence descriptions, it is assumed that the CPU is the master and the RX8804CE is the slave. a. Address specification write sequence Since the RX8804CE includes an address auto increment function, once the initial address has been specified, the RX8804CE increments (by one byte) the receive address each time data is transferred.

  • Page 42: Backup And Recovery

    RX8804CE 8.10. Backup and Recovery Back-up operation C-Bus Communication state Communication Non-Communication Non-Communication Figure 25 V Sequence This circuit is sensitive to power supply noise and supply voltage should be stabilized to avoid negative impact on the accuracy. tR1 is needed for a proper power-on reset. If this power-on condition cannot be kept, it is necessary to send an initialization routine to the RTC by software.

  • Page 43: About Access At The Time Of Backup Return And Initial Power Supply

    RX8804CE 8.11. About Access at the Time of Backup Return and Initial Power Supply Because most of RTC registers are synchronized with the oscillation clock of the built-in crystal oscillator, the RTC does not work normally without the integrated oscillator having stabilized. Please initialize the RTC at the time the power supply voltage returns (VLF = 1) after the oscillation has stabilized (after oscillation start time tSTA).

  • Page 44: Flow Chart

    RX8804CE 8.12. Flow Chart The following flow-chart is one example, but it is not necessarily applicable for every use-case and not necessarily the most effective process for individual applications. 1) An example of the initialization Initialization • Cleart TE bit to “0”. Clear TEST bit to “0”...
  • Page 45 RX8804CE 2) Method of initialization after starting of internal oscillation (VLF stays “0”) power on • Wait time of 30 ms is necessary at least Wait VLF = 1 ? • Whether it is a return from the state of the backup is confirmed •...
  • Page 46 RX8804CE 3) The setting of the clock and calendar Set time • Set RESET bit to 1 to prevent timer update in time setting Set RESET to 1 • Write information of [year / month /date [day of the week] hour:...

  • Page 47: Connection With Typical Microcontroller

    RX8804CE 8.13. Connection with Typical Microcontroller 0.1 µF C-Bus master MCU Sensor RX8804CE EVIN Module R = 2 kΩ to 10 kΩ Figure 31 Circuit Diagram 8.14. When Used as a Clock Source (32.768 kHz DTCXO) RX8804CE 0.1 F FOUT 32.768 kHz...

  • Page 48: External Dimensions / Marking Layout

    RX8804CE 9. External Dimensions / Marking Layout 9.1. RX8804CE 9.1.1. External Dimensions • External dimensions • Recommended soldering pattern 3.2 ± 0.2 2.5 ± 0.2 1.0 Max. 0. 7 0. 4 0.2 Min. 0.62 0.42 0.35 *1. The small metal pads on the short side of the ceramic package are used to test the crystal.

  • Page 49: Application Notes

    RX8804CE 10.Application Notes 1) Notes on handling This module uses a CMOS IC to realize low power consumption. Carefully note the following cautions when handling. (1) Static electricity While this module has built-in circuitry designed to protect it against electrostatic discharge, the chip could still be damaged by a large discharge of static electricity.

  • Page 50: Figures

    RX8804CE 11.Figures Figure 1 Block Diagram ..............................1 Figure 2 Pin Layout ................................ 2 Figure 3 I C-Bus Timing Chart ............................5 Figure 4 Temperature compensation current ......................... 6 Figure 5 I C-Bus Current consumption .......................... 6 Figure 6 Internal clock distribution diagram ....................... 10 Figure 7 EVIN Debounce Function ..........................
  • Page 51 RX8804CE Table 32 EPU bit ................................15 Table 33 RCE bit ................................15 Table 34 EF bit ................................15 Table 35 ET bit ................................16 Table 36 EIE bit................................16 Table 37 EVMON bit ..............................16 Table 38 Alarm Interrupt Function Register ......................... 21 Table 39 WADA bit ...............................
  • Page 52 Unit 715-723 7/F Trade Square, 681 Cheung Sha Wan Road, Kowloon, Hong Kong Phone: (86) 755-2699-3828 (Shenzhen Branch) Fax: (86) 755-2699-3838 (Shenzhen Branch) www.epson.com.hk Epson Taiwan Technology & Trading Ltd. 15F, No.100, Songren Rd.,Sinyi Dist., Taipei City 110, Taiwan Phone: (886) 2-8786-6688 Fax: (886)2-8786-6660 www.epson.com.tw/ElectronicComponent...

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