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Epson RA8900SA Applications Manual
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Epson RA8900SA Applications Manual

Epson RA8900SA Applications Manual

Real time clock module
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ETM44E-03
l
Application Manua
Real Time Clock Module
RA8900SA / CE
Preliminary

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Summary of Contents for Epson RA8900SA

  • Page 1 ETM44E-03 Application Manua Real Time Clock Module RA8900SA / CE Preliminary...
  • Page 2 The information about applied circuitry, software, usage, etc. written in this material is intended for reference only. Seiko Epson does not assume any liability for the occurrence of infringing on any patent or copyright of a third party. This material does not authorize the licensing for any patent or intellectual copyrights.
  • Page 3 RA8900 SA / CE Contents 1. Overview ........................2 2. Block Diagram ....................... 2 3. Terminal description ...................... 3 3.1. Terminal connections ........................3 3.2. Pin Functions ............................ 3 4. Absolute Maximum Ratings ................... 4 5. Recommended Operating Conditions ................4 6.
  • Page 4 RA8900 SA / CE 9. External Dimensions / Marking Layout ................. 38 10. Application notes ....................... 40 Page - 1 ETM44E-03...
  • Page 5 RA8900 SA / CE For automotive I C-Bus Interface Real-time Clock Module RA8900 SA / CE • Features built-in 32.768 kHz DTCXO, High Stability. • Supports I C-Bus's high speed mode (400 kHz) • Alarm interrupt function for day, date, hour, and minute settings •...
  • Page 6 RA8900 SA / CE 3. Terminal description 3.1. Terminal connections RA8900CE RA890 0SA 1. FOE 10. / INT 1. T1 (CE) 14. N.C. 2. V 9. GND 2. SCL 13. SDA 3. V 8. T2 (V 3. FOUT 12. T2 (V 4.
  • Page 7 RA8900 SA / CE 4. Absolute Maximum Ratings GND = 0 V Item Symbol Condition Rating Unit −0.3 to +6.5 Supply voltage (1) Between V and GND −0.3 to +6.5 Supply voltage (2) Between V and GND Input voltage (2) FOE,SCL, SDA pins GND−0.3 to +6.5 Output voltage (1)
  • Page 8 RA8900 SA / CE 7. Electrical Characteristics = 2.5 V to 5.5 V, Ta = −40 °C to +85 °C 7.1. DC Characteristics *Unless otherwise specified, GND = 0 V, V Item Symbol Condition Min. Typ. Max. Unit Current = 0 Hz, / INT = V = 5 V 0.72 1.50...
  • Page 9 RA8900 SA / CE * Unless otherwise specified, 7.2. AC Characteristics = 2.5 V to 5.5 V , Ta = −40 °C to +85 °C GND = 0 V , V Item Symbol Condition Min. Typ. Max. Unit SCL clock frequency µs Start condition setup time SU;STA...
  • Page 10 RA8900 SA / CE 8. Use Methods 8.1. Description of Registers 8.1.1. Write / Read and Bank Select … C Address 00h to 0Fh : Basic time and calendar register ompatible with RX-8803. Address 10h to 1Fh : Extension register 8.1.2.
  • Page 11 RA8900 SA / CE 8.1.3. Register table (Extension register) Read Write Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 HOUR WEEK MONTH YEAR TEMP VDET Backup Function SWOFF BKSMP1 BKSMP0 Not use Not use Timer Counter 0...
  • Page 12 RA8900 SA / CE 8.2. Details of Registers 8.2.1. Clock counter (SEC - HOUR ) Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 00, 10 01, 11 02, 12 HOUR ∗) "o"...
  • Page 13 RA8900 SA / CE 8.2.2. Calendar counter ( WEEK - YEAR ) Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 03, 13 WEEK ∗) "o" indicates write-protected bits. A zero is always read from these bits. 1) Day of the WEEK counter •...
  • Page 14 RA8900 SA / CE 8.2.3. Alarm registers Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 MIN Alarm • HOUR Alarm WEEK Alarm • DAY Alarm • The alarm interrupt function is used, along with the AEI, AF, and WADA bits, to set alarms for specified date, day, hour, and minute values.
  • Page 15 RA8900 SA / CE 5) FSEL0,1 ( FOUT frequency Select 0, 1 ) bits The combination of these two bits is used to set the FOUT frequency. FSEL1 FSEL0 FSEL0,1 FOUT frequency (bit 3) (bit 2) ∗ Default 32768 Hz Output 1024 Hz Output Write/Read 1 Hz Output...
  • Page 16 RA8900 SA / CE 5) VDET ( Voltage Detection Flag ) bit This flag bit indicates the status of temperature compensation. Its value changes from "0" to "1" when stop the temperature compensation, such as due to a supply voltage drop. Once this flag bit's value is "1", its value is retained until a "0"...
  • Page 17 RA8900 SA / CE Data Function When a time update interrupt event occurs, an interrupt signal is not generated or is canceled (/INT status changes from low to Hi-Z). When a time update interrupt event occurs, an interrupt signal is Write/Read generated (/INT status changes from Hi-Z to low).
  • Page 18 RA8900 SA / CE 8.2.8. Temperature Data register Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 TEMP 1) Temperature Data register This register can begin to read digital temperature data. The temperature data are updated in an operation timing of the temperature compensation circuit.
  • Page 19 RA8900 SA / CE 8.3. Fixed-cycle Timer Interrupt Function The fixed-cycle timer interrupt generation function generates an interrupt event periodically at any fixed cycle set between 244.14 µs and 4095 minutes. When an interrupt event is generated, the /INT pin goes to low level and "1" is set to the TF bit to report that an event has occurred.
  • Page 20 RA8900 SA / CE 8.3.2. Related registers for function of time update interrupts. Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 0B, 1B Timer Counter 0 • • • • 0C, 1C Timer Counter 1 2048...
  • Page 21 RA8900 SA / CE 5) TIE (Timer Interrupt Enable) bit When a fixed-cycle timer interrupt event occurs (when the TF bit value changes from "0" to "1"), this bit's value specifies whether an interrupt signal is generated (/INT status changes from Hi-Z to low) or is not generated (/INT status remains Hi-Z).
  • Page 22 RA8900 SA / CE 8.4. 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 23 RA8900 SA / CE 8.4.2. Related registers for time update interrupt functions. Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 0D, 1D Extension Register USEL TEST WADA FSEL1 FSEL0 TSEL1 TSEL0 0E, 1E Flag Register...
  • Page 24 RA8900 SA / CE 8.5. Alarm Interrupt Function The alarm interrupt generation function generates interrupt events for alarm settings such as date, 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 25 RA8900 SA / CE 8.5.2. Related registers Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 01, 12 02, 13 HOUR 03, 14 WEEK 04, 15 08, 18 MIN Alarm • 09, 19 HOUR Alarm WEEK Alarm...
  • Page 26 RA8900 SA / CE 3) 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. Data Description The AF bit is cleared to zero to prepare for the next status detection...
  • Page 27 RA8900 SA / CE 8.6. About the interrupt function for operation /INT=”L” interrupt output. How to identify events when the interrupt output occurred. /INT output pin is common output terminal of interrupt events of three types (Fixed-cycle timer Time interrupt , alarm interrupt, time update interrupt).
  • Page 28 RA8900 SA / CE 8.8. Battery backup switchover function 8.8.1. Description of Battery backup switchover function It consists of the power-source detector "VDET" which detect the power down of the main power source "VDD", and built-in MOS switches located between the main power-source pin "VDD" and the backup power supply pin "VBAT". In turning off a MOS switch according to the supply-voltage detection result of VDET, when an drive power source changes to VDD OFF ->VBAT (it shifts to a backup operation from a normal operation), it becomes possible to prevent a reverse-current (VBAT->VDD) of an electric current.
  • Page 29 RA8900 SA / CE 8.8.2. Control the contents of the power switching BACKUP state PMOS switch is turned off at all times. Voltage detection VDET3 is responsible for monitoring every 1sec. This state will be selected at cold start. Make the voltage detection for the first time in 1sec after since it was powered on VDD pin.
  • Page 30 RA8900 SA / CE 8.8.4. Notes on power switching function is used 1.Please make VDD = 0V, when you backup. If the VDD voltage is lower than VACCSW(2), there is an unnecessary current flows through the input and output circuit. The transition to the backup from NORMAL state, please set to VDD = 0V promptly. Also, when returning from a backup, please set to VDD level of desired promptly.
  • Page 31 RA8900 SA / CE 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 32 RA8900 SA / CE 8.9.3. Starting and stopping I C bus communications START Repeated START(RESTART) STOP condition condition condition [ S ] [ Sr ] [ P ] 0.95 s ( Max. ) 1) START condition, repeated START condition, and STOP condition (1) START condition •...
  • Page 33 RA8900 SA / CE 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. (However, the transfer time must be no longer than 0.95 seconds.) The address auto increment function operates during both write and read operations.
  • Page 34 RA8900 SA / CE 8.9.6. I C bus protocol In the following sequence descriptions, it is assumed that the CPU is the master and the RA8900 is the slave. a. Address specification write sequence Since the RA8900 includes an address auto increment function, once the initial address has been specified, the RA8900 increments (by one byte) the receive address each time data is transferred.
  • Page 35 RA8900 SA / CE 8.10. Backup and Recovery *This standard does not mean power supply noise tolerance. It is more than 60 seconds for a backup operation term. * tR1 is restrictions to validate power-on reset. When cannot keep this standard, power-on reset does not work normally.
  • Page 36 RA8900 SA / CE 8.11. About access at the time of backup return and Initial power supply Because of most of RTC registers synchronize to an oscillation clock of a built-in crystal oscillator , RTC does not work normally in a without inside oscillation. Please perform initial setting at the time of power supply voltage return from the state that an oscillation stopped after progress in oscillation start time.
  • Page 37 RA8900 SA / CE 8.12. Flow chart The following flow-chart is one instance. Mention for easy understanding takes precedence over others; therefore there are some inefficient cases for the actual processing. If you wish to take more efficient process, perform some processes at the same time or try to confirm and adjust some part where is no hindered from transposing of operation procedure.
  • Page 38 RA8900 SA / CE 2) Method of initialization after starting of internal oscillation The Initialize is possible in 30ms since Internal VDD becomes higher than bottom value of clock supply voltage. Even in this case, after an internal oscillation begins, it is necessary to clear VLF= “0”. power on •...
  • Page 39 RA8900 SA / CE 3) The setting of a clock and calendar Set time • Set RESET bit to “1” to prevent timer update in time setting. RESET ← " 1 " • Write information of [ year / month /date [day of the week] hour: minute: second ] which is necessary to set (or reset).
  • Page 40 RA8900 SA / CE 8.13. Connection with Typical Microcontroller Note I C-BUS Master RA8900 SLAVE ADRS = 0110 010* Pull up Registor C Bus ) Note : It uses the secondary battery. For detailed value on the resistance, please consult a battery maker. [Connection example not using Battery backup switchover function] Please connect a main power supply to both VDD and VBAT terminals.
  • Page 41 RA8900 SA / CE 9. External Dimensions / Marking Layout 9.1. RA8900SA 9.1.1. External dimensions ( SOP − 14pin ) RA8900SA • External dimensions • Recommended soldering pattern ± 10.1 0° - 10° ± 5.0 7.4 0.15 1.27 1.27 × 6 = 7.62 0.05...
  • Page 42 RA8900 SA / CE 9.2. RA8900CE 9.2.1. External dimensions RA8900CE • External dimensions • Recommended soldering pattern 3.2 ± 0.2 Unit : mm 0.42 0.35 The small metal part are used for test of crystal. These are on edge of a short side of package.(4points) Please assemble carefully not to let these metal parts short-circuit. In addition, please avoid short circuit between these metal parts by dew condensation or particle adhesion.
  • Page 43 RA8900 SA / CE 10. Application notes 1) Notes on handling This module uses a C-MOS 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 44 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) http://www.epson.com.hk Epson Taiwan Technology & Trading Ltd. 14F, No.7, Song Ren Road, Taipei 110 Phone: (886) 2-8786-6688 Fax: (886)2-8786-6660 http://www.epson.com.tw/ElectronicComponent Epson Singapore Pte.

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