SP7682EB datasheet(12/19 Pages) EXAR

12 / 19 page

Sept 27-07 rev G

SP7682: Backlight and Flash Driver

Page 12

APPLICATIONS INFORMATION

2C Specifications

The I

2C protocol defines any device that sends data

to the bus as a transmitter and any device that reads

the data as a receiver. The device that controls the

data transfer is known as the master and the other

device as the slave. The master will always initiate a

data transfer and will provide the serial clock for

synchronization.

Data input format:

SP7682 Address

7-bit

1/0

Data for

Status1

8-bit

Data for

Status2

8-bit

Data

For

LED

8-bit

Data

for

Flash

8-bit

SP7682 I

2C Slave Address Map: (7-bit Default Address: 0x28)

Fuses

Device Address

R/W

1/0

7-bit

address

Hex

Fuse1

Fuse0

A7-A1

0x28

0x20

0x38

0x30

Theory of Operation - I²C Serial Interface

The SP7682 has four data registers which can be

programmed serially via the I²C interface. The first

for shutdown/power up options, 4 bits used for

individual backlight LED ON/OFF control, and 2 bits

for charge pump mode.

The second STATUS

Temperature OK, Voltage OK, and Flash time-out

expired conditions. After the Flash timeout has

expired the FTO bit will toggle on and then off for

intervals set by the TDO bits. The next two registers

are used to set the brightness levels of the backlight

LEDs and Flash LED.

The register bits are as follows:

STATUS1

PMP0

PMP1

LED0

LED1

LED2

LED3

STATUS2

TOUT0

TOUT1

TD0

TD1

TOK

VOK

FTO

LEDS

FLASH

Acknowledge, sent by slave when R/

W =0

Or, sent by master when R/

W =1

Stop

condition

Start

Condition

Acknowledge,

sent by slave

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