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Epson RX-8581JE, RX-8581NB, RX-8581SA SCL, SDA, Min, Typ, Max, kHz, Item, Unit, Page, tW /t, Symbol, MQ372-02, Condition, FOUT duty, Timing chart, 0.95 seconds, Data hold time, Data setup time

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RX - 8581 SA / JE / NB

7.2. AC Characteristics

*Unless otherwise specified, GND = 0 V , VDD = 1.8 V to 5.5 V , Ta = − 40 ° C to +85 ° C

	Item	Symbol	Condition	Min.	Typ.	Max.	Unit

	SCL clock frequency	fSCL				400	kHz
	Start condition setup time	tSU;STA		0.6			∝ s
	Start condition hold time	tHD;STA		0.6			∝ s
	Data setup time	tSU;DAT		100			ns
	Data hold time	tHD;DAT		0			ns
	Stop condition setup time	tSU;STO		0.6			∝ s
	Bus idle time between	tBUF		1.3			∝ s
	start condition and stop condition	tBUF		1.3			∝ s
	start condition and stop condition
	Time when SCL = "L"	tLOW		1.3			∝ s
	Time when SCL = "H"	tHIGH		0.6			∝ s
	Rise time for SCL and SDA	tr				0.3	∝ s
	Fall time for SCL and SDA	tf				0.3	∝ s
	Allowable spike time on bus	tSP				50	ns
	FOUT duty	tW /t	VDD = 2.4 V ∼ 5.5 V	45	50	55	%
	FOUT duty	tW /t	50% of VDD level	45	50	55	%
			50% of VDD level

	Timing chart

Protocol

START

BIT 7

BIT 6

BIT 0

ACK

STOP

START

CONDITION

MSB

LSB

CONDITION

CONDITION

(S)

(A7)

(A6)

(R/W)

(A)

(P)

(S)

tSU ; STA tLOW tHIGH 1 / fSCLtSU ; STA

SCL

(S)

(P)

(S)

tBUF

tr

tf

SDA

(A)

tHD ; STA

tSU ; DAT

tHD ; DAT

tSP

tSU ; STO

tHD ; STA

Caution: When accessing this device, all communication from transmitting the start condition to transmitting the stop condition after access should be completed within 0.95 seconds.

If such communication requires 0.95 seconds or longer, the I2C bus interface is reset by the internal bus timeout function.

Page - 4

MQ372-02

Contents

Page In pursuit of "Saving" Technology ,Epson electronic device "Saving Epson IS energy savings •The material is subject to change without notice 7.1. DC characteristics Page MQ372-02 RX - 8581 SA RX - 8581 JE RX - 8581 NB Signal I/O Item Symbol Condition Rating Unit SCL SDA 8.1. Overview of Functions 1) Clock functions 2)Fixed-cycleinterrupt generation function 3)Time update interrupt function 4)Alarm interrupt function 5)32.768-kHzclock output Address 8.2.2. Control register (Reg F) STOP RESET 1) UIE (Update Interrupt Enable) bit When a time update interrupt event occurs, an interrupt signal is not 4) STOP bit Writing a "0" to this bit cancels stop status (restarts operations) STOP Description [Normal operation mode] 8.2.3. Flag register (Reg-E) Flag register ∗ 1) ∗ 2) 1)UF (Update Flag) bit 8.2.4. Extension register (Reg-D) WADA USEL TSEL1 ∗ 3) Page Page 8.3. Fixed-cycleTimer Interrupt Function 8.3.1. Diagram of fixed-cycletimer interrupt function TE bit TIE bit /INT output 8.3.2. Related registers for function of time update interrupts TSEL1 TSEL0 interrupts from occurring inadvertently while entering settings When the SCL pin SDA pin /INT pin 8.4.1. Time update interrupt function diagram (2)When a time update interrupt event occurs, the UF bit value becomes "1 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 8.4.2. Related registers for time update interrupt functions 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 Page 8.5.2. Related registers from occurring inadvertently while entering settings 1) WADA (Week Alarm /Day Alarm) bit WADA Sets WEEK as target of alarm function 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 8.6.3. Starting and stopping I2C bus communications 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 8.6.4.Data transfers and acknowledge responses during I2C-BUScommunications 1)Data transfers However, the transfer time must be no longer than 0.95 seconds After address Fh, incrementation goes to address 0h 2)Data acknowledge response (ACK signal) Page Page RX-8581SA (SOP - 14 pin) •External dimensions R8581 E 1234A •Recommended soldering Page (1) Static electricity (2) Noise (3)Voltage levels of input pins (4) Handling of unused pins 11.2.Notes on packaging Distributor AMERICA EPSON ELECTRONICS AMERICA, INC HEADQUARTER 150 River Oaks Parkway, San Jose, CA 95134, U.S.A