RX8025SA EPSON Electronics, RX8025SA Datasheet

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RX8025SA

Manufacturer Part Number
RX8025SA
Description
Real-Time Clock
Manufacturer
EPSON Electronics
Datasheet

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RX8025SA
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EPSON/爱普生
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RX8025SA-AC
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RX-8025 SA/NB
1. Overview
2. Block Diagram
I
RX-8025 SA/NB
interrupt flags and interrupt stop function)
2
( 5
Supports I
Includes time (H/M/S) and calendar (YR/MO/DATE/DAY) counter functions (BCD code)
Built-in high-precision clock precision control logic
CPU interrupt generation function (cycle time range: 1 month to 0.5 seconds, includes
Dual alarm functions (Alarm_W: Day/Hour/Min, Alarm_D: Hour/Min)
32.768 kHz clock output (CMOS output with control pin)
Oscillation stop detection function (used to determine presence of internal data)
Power supply voltage monitoring function (with selectable detection threshold)
Features built-in 32.768 kHz quartz oscillator, frequency adjusted for high precision
Wide clock voltage range: 1.15 V to 5.5 V
Wide interface voltage range: 1.7 V to 5.5 V
Low current consumption: 0.48 A/3.0 V (Typ.)
C-Bus Interface Real-time Clock Module
This module is an I
that has been adjusted for high precision. In addition to providing a function for generating six types of
interrupts, a dual alarm function, an oscillation stop detection function (used to determine presence of valid
internal data at power-on), and a power supply voltage monitoring function, this module includes a digital clock
precision adjustment function that can be used to set various levels of precision.
Since the internal oscillation circuit is driven at a constant voltage, 32.768 kHz clock output is stable and free
of voltage fluctuation effects.
This implementation of multiple functions in one SMT package is ideal for applications ranging from cellular
phones to PDAs and other small electronic devices.
FOUT
FOE
/ INTA
/ INTB
10 6 when Ta = +25 C)
Select between 12-hr and 24-hr clock display
Auto calculation of leap years until 2099
2
C-Bus's high speed mode (400 kHz)
2
C bus interface-compliant real-time clock which includes a 32.768 kHz quartz oscillator
Control
Detect
32 kHz
Output
OSC
OSC
Interrupt Control
Divider
Correc
-tion
Div.
Page - 1
Comparator_W
Comparator_D
( Sec,Min,Hour,Day,Date,Month,Year )
Address
Decoder
Time Counter
Shift Register
Alarm_W Register
Alarm_D Register
( Min,Hour,Day)
Address
Register
( Min,Hour )
Preliminary
Control
Voltage
Detect
I/O
2002.08 Ver.0.1
SCL
V
SDA
GND
DD

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RX8025SA Summary of contents

Page 1

RX-8025 SA/ C-Bus Interface Real-time Clock Module RX-8025 SA/NB Features built-in 32.768 kHz quartz oscillator, frequency adjusted for high precision 10 6 when Supports I C-Bus's high speed mode (400 kHz) ...

Page 2

RX-8025 SA/NB 3. Description of Pins 3.1. Pin Layout RX - 8025 SA 1. N.C. 2. SCL 3. FOUT 4. N.C. 5. TEST FOE SOP - 14pin 3.2. Pin Functions Signal name This ...

Page 3

RX-8025 SA/NB 4. Absolute Maximum Ratings Item Symbol Supply voltage V DD Input voltage Output voltage V O2 Storage temperature T STG 5. Operating Conditions Item Symbol Power voltage V DD Clock voltage V CLK Operating ...

Page 4

RX-8025 SA/NB 7.1.2. DC electrical characteristics (2) Item Symbol Input current with pull-down I FOE resistance Output current when OFF I OZ High-voltage Power V DETH supply mode detection Low-voltage V DETL voltage mode 7.2. AC Electrical Characteristics Unless otherwise ...

Page 5

RX-8025 SA/NB 8. Functional descriptions 8.1. Overview of Functions 1) Clock functions These functions enable setting, timing, and display of data including the year (last two digits), month, date, day, hour, minute, and second. Any (two-digit) year that is a ...

Page 6

RX-8025 SA/NB 8.2. Description of Registers 8.2.1. Register table Address Function 0 Seconds 1 Minutes 2 Hours 3 Days 4 Days 5 Months 6 Years 7 Digital Offset 8 Alarm_W ; Minute 9 Alarm_W ; Hour A Alarm_W ; Day ...

Page 7

RX-8025 SA/NB 8.2.2. Control register 1 (Reg E) Address Function E Control 1 (Default) ) The default value is the value that is read (or is set internally) after the PON bit has been set to "1," such as after ...

Page 8

RX-8025 SA/NB 8.2.3. Control register 2 (Reg F) Address Function F Control 2 (Default) 1) The default value is the value that is read (or is set internally) after the PON bit has been set to "1," such as after ...

Page 9

RX-8025 SA/ bit Bits marked with " " are RAM bits that can contain any value and are read/write-accessible. However, these bits are cleared to zero when the PON bit value is "1". 6) CTFG bit During ...

Page 10

RX-8025 SA/NB 8.2.4. Time counter (Reg Address Function 0 Seconds 1 Minutes 2 Hours □ ) " " indicates write-protected bits. A zero is always read from these bits. The time counter counts seconds, minutes, and hours. ...

Page 11

RX-8025 SA/NB 8.2.5. Day counter (Reg 3) Address Function 3 Days □ ) " " indicates write-protected bits. A zero is always read from these bits. The day counter is a divide-by-7 counter that counts from and ...

Page 12

RX-8025 SA/NB 8.2.7. Clock precision adjustment register (Reg 7) Address Function 7 Digital Offset (Default) ) 'Be sure to set a "0" for any bit whose value is shown above as "0". A zero is returned when any of these ...

Page 13

RX-8025 SA/NB 8.3. Clock Precision Adjustment Function The clock precision can be set ahead or behind. This function can be used to implement a higher-precision clock function, such as by: Enabling higher clock precision throughout the year by taking seasonal ...

Page 14

RX-8025 SA/NB 8.3.3. Adjustment examples Example 1) Setting time forward Objective) To adjust (advance) the clock precision when FOUT clock output is 32767.7 Hz (1) Determine the current amount of variance 32767.7 Hz (2) Calculate the optimum adjustment data (decimal ...

Page 15

RX-8025 SA/NB 8.4. Periodic Interrupt Function Periodic interrupt output can be obtained via the /INTA pin. Select among five periodic-cycle settings (once per 0.5 seconds (once per second), 1/60 Hz (once per minute), 1/3600 Hz (once ...

Page 16

RX-8025 SA/NB 8.4.2. Mode-specific output waveforms 1) Pulse mode A 2-Hz or 1-Hz clock pulse is output. The relation between the clock pulse and the count operation is shown below. CTFG bit /INTRA pin Note shown in ...

Page 17

RX-8025 SA/NB 8.5. Alarm W function The Alarm W function generates interrupt signals (output via the /INTB pin) that correspond to specified days, hours, and minutes. For description of the Alarm D function, which supports only hour and minute data, ...

Page 18

RX-8025 SA/NB 3) /12, 24 bit This bit is used to select between 12-hour clock operation and 24-hour clock operation. /12,24 Data Write / Read Be sure to select between 12-hour and 24-hour clock operation before writing the time data. ...

Page 19

RX-8025 SA/NB 8.6. Alarm D function The Alarm D function generates interrupt signals (output via the /INTA pin) that correspond to specified hours and minutes. For description of the Alarm W function, which supports only day, hour, and minute data, ...

Page 20

RX-8025 SA/NB 8.7. The various detection Functions The detection functions include detection of power-on resets, oscillation stops, and supply voltage drops, as well as reporting of detection results in corresponding bits of the address Fh (Control 2) register. The status ...

Page 21

RX-8025 SA/NB 8.7.2. Oscillation stop detection This function detects when internal oscillation has stopped. When an oscillation stop is detected, the /XST bit value becomes "0" "1" has already been written to the /XST bit, the /XST bit ...

Page 22

RX-8025 SA/NB 8.7.4. Estimation of status based on detection results The power supply status and clock status can be confirmed by reading the detection results indicated by the PON, /XST, and VDET bits. The following are status estimates based on ...

Page 23

RX-8025 SA/NB 8.8. Reading/Writing Data via the I 8.8.1. Overview C-BUS 2 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 ...

Page 24

RX-8025 SA/NB 2 8.8.3. Starting and stopping I C bus communications START condition SCL SDA 1) START condition, repeated START condition, and STOP condition (1) START condition This condition regulates how communications on the I 2 C-BUS are started. SDA ...

Page 25

RX-8025 SA/NB 8.8.4. Data transfers and acknowledge responses during I 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 ...

Page 26

RX-8025 SA/NB 2 8.8. bus's basic transfer format The write/read steps are illustrated below. Master is transmitter (sending side), RTC is receiver (receiving side) Master is receiver (receiving side) RTC is transmitter (sending side Write via ...

Page 27

RX-8025 SA/NB 8.9. External Connection Example V DD Note : Pull-up resistor connections. SCL and SDA Connect to the system-power-supply. / INTA and / INTB When using these interrupt signals at battery backup, connect these pins to backup power supply. ...

Page 28

RX-8025 SA/NB 9. External Dimensions/Marking Layout 9.1. External Dimensions RX-8025 SA (SOP-14pin) External dimensions 10.1 0.2 # 0.35 1.27 The quartz oscillator's metal case may be visible in the area (on top) indicates in broken lines no ...

Page 29

RX-8025 SA/NB 10. Reference Data (1) Example of frequency/temperature characteristics = +25 C Typ Typ 0.035 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 -110 -120 -130 -140 ...

Page 30

RX-8025 SA/NB 11. Cautions for Use 11.1. Handling precautions Since this module includes a quartz oscillator, be careful to protect it from heavy impact or vibration. Also, be sure to note the following caution points regarding the C-MOS IC that ...

Page 31

RX-8025 SA/NB 1. Overview ..................................................................................................................1 2. Block Diagram ..........................................................................................................1 3. Description of Pins....................................................................................................2 3.1. Pin Layout ....................................................................................................................................2 3.2. Pin Functions ...............................................................................................................................2 4. Absolute Maximum Ratings 6. Frequency Characteristics 7. Electrical Characteristics................................................................................................3 8. Functional descriptions .............................................................................................5 8.1. Overview of Functions..................................................................................................................5 8.2. ...

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