Manuals / Brands / Computer Equipment / Clock / Epson / Computer Equipment / Clock

Epson RX-8801SA/JE Page, ETM26E-03, 8.4. Time Update Interrupt Function

1 34

Download 34 pages, 517.83 Kb

RX − 8801 SA / JE

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. (However, when a fixed-cycle timer interrupt event has been generated, low-level output from the /INT pin occurs only when the value of the control register's UIE bit is "1". This /INT status is automatically cleared (/INT status changes from low level to Hi-Z) 7.8 ms (fixed value) after the interrupt occurs.

∗ /INT operation example

7.8ms

UIE = " 1 "

period

UIE = " 1 " → " 0 "

8.4.1. Time update interrupt function diagram

" 1 "

(7)

UIE bit	(4)			" 1 "
	(4)
				" 0 "
				" 0 "
/INT output				Hi - z
/INT output	(5)			" L "
	(5)			" L "
	tRTN	tRTN	tRTN	tRTN
		(6)

(3)

∗ /INT status does not

UF bit

(2)

change when UF bit is

cleared to zero.

period

period

period

period

Events

(1)

Operation in RTC

Write operation

" 1 " " 0 "

(1)A time update interrupt event occurs when the internal clock's value matches either the second update time or the minute update time. The USEL bit's specification determines whether it is the second update time or the minute update time that must be matched.

(2)When a time update interrupt event occurs, the UF bit value becomes "1".

(3)When the UF bit value is "1" its value is retained until it is cleared to zero.

(4)When a time update interrupt occurs, /INT pin output is low if UIE = "1".

∗If UIE = "0" when a timer update interrupt occurs, the /INT pin status remains Hi-Z.

(5)Each time an event occurs, /INT pin output is low only up to the tRTN time (which is fixed as 7.1825 ms for time update interrupts) after which it is automatically cleared to Hi-Z.

∗/INT pin output goes low again when the next interrupt event occurs.

(6)As long as /INT = low, the /INT pin status does not change, even if the UF bit value changes from "1" to "0".

(7)When /INT = low, the /INT pin status changes from low to Hi-Z as soon as the UIE bit value changes from "1" to "0".

Page - 17

ETM26E-03

Contents

Page NOTICE RX - 8801 SA / JE Contents 2. Block Diagram 3. Terminal description 4. Absolute Maximum Ratings I2C-BusInterface Real-timeClock Module 1. Overview 2. Block Diagram 3. Terminal description RX − 8801 SA RX − 8801 JE 4. Absolute Maximum Ratings Item Symbol Condition Rating 7. Electrical Characteristics •Temperature compensation and consumption current Protocol SCL SDA 8. Use Methods 8.2. Description of Registers 8.2.1. Register table Address Remark SEC MIN 8.2.2. Control register (Reg F) Control Register CSEL1 1) CSEL0,1 ( Compensation interval Select 0, 1 ) bits CSEL0,1 3) AIE ( Alarm Interrupt Enable ) bit When an alarm interrupt event occurs, an interrupt signal is not generated or is canceled (/INT status changes from low to Hi-Z) When an alarm interrupt event occurs, an interrupt signal is generated (/INT status changes from Hi-Zto low) Flag register 1)UF ( Update Flag ) bit 2)TF ( Timer Flag ) bit 3)AF ( Alarm Flag ) bit 4)VLF ( Voltage Low Flag ) bit Extension Register USEL TSEL1 1)TEST bit This is the manufacturer's test bit. Its value should always be "0 8.2.6. Clock counter (Reg - 0 ∼ 2) •The clock counter counts seconds, minutes, and hours The data format is BCD format 1) Second counter 00 seconds Month Date update pattern 1, 3, 5, 7, 8, 10, or 4, 6, 9, or February in normal year 8.3. Fixed-cycleTimer Interrupt Function 8.3.1. Diagram of fixed-cycletimer interrupt function TE bit TIE bit /INT output TSEL1 TSEL0 Flag Register When the 1) TSEL0,1 bits (Timer Select 0, 1) SCL pin SDA pin /INT pin 8.4. Time Update Interrupt Function ∗When the RESET bit value is "1" time update interrupt events do not occur 1) USEL (Update Interrupt Select) bit Selects "second update" (once per second) as the timing for generation of interrupt events Selects "minute update" (once per minute) as the timing for generation of 8.5. Alarm Interrupt Function ∗When the RESET bit value is "1" alarm interrupt events do not occur 1) WADA (Week Alarm /Day Alarm) bit WADA Sets WEEK as target of alarm function (DAY setting is ignored) 3) AF (Alarm Flag) bit The AF bit is cleared to zero to prepare for the next status detection Alarm interrupt events are not detected Alarm interrupt events are detected 4) AIE (Alarm Interrupt Enable) bit 8.6. Reading/Writing Data via the I2C Bus Interface 0.95 s ( Max. ) 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 (2)STOP condition However, the transfer time must be no longer than 0.95 seconds After address Fh, incrementation goes to address 0h [0110 65 h 64 h Page Unit I2C-BUS Master RX-8801 9. External Dimensions / Marking Layout 9.1. RX − 8801 SA ( SOP − 14pin ) ( SOP 14pin ) 9.1.1. External dimensions 9.2.RX − 8801 JE ( VSOJ − 20pin ) 9.2.1. External dimensions RX − 8801 JE ( VSOJ − 20pin ) • External dimensions • Recommended soldering pattern 10.Application notes 1)Notes on handling 2) Notes on packaging AMERICA EUROPE Distributor Electronic devices information on WWW server http://www.epsontoyocom.co.jp