4

LED Control IC

W2RF004RM

Operation

■ Functional Overview

Receiving Commands

The IC recieves commands with two-wire serial communication to control 9 LED lines. Commands are received in a 40-bits-per-command com-

munication format.

Gradation Control

The lighting of the 9 LED lines is controlled individually or by group with 16-level lighting gradation and 32-level lighting speed. The exponential

control of output duty cycle allows lighting gradation that matches the human visual characteristics. In addition, the specification of lighting speed

allows fade-in and fade-out with up to 1,024 levels.

Number of Control Lines

The IC has two device address lines, each of which can be configured in seven ways by terminal configuration. This provides up to 49 patterns of

device address configuration, allowing up to 441 lines to be controlled on the same communication line. Two device address lines can be combined

to configure a device group.

■ Communication Specifications

Input signals to SDA-I and SCL-I are input via the filter circuit (0.1

μs delay) to the communication circuit. An SDA-I signal that is input to the com-

munication circuit is taken in as serial data at the rising edge of an SCL-I signal. When serial data is received in a different format from the com-

munication format, the data will be invalid.

When the START signal, “111111111” is detected, the communication circuit takes in data as new serial data, whether it is on stand-by or in the

middle of intake of serial data.

Input signals to SDA-I and SCL-I will be output via the asynchronous buffer to SDA-O and SCL-O without going through the filter circuit.

Description of Communication Format

■ Control Command

Device Selection Data (8 bits)

The device ID is fixed. The correspondence between the device addresses A and B and the setting terminals ADRA0 to 2 and ADRB0 to 2 is shown

in the table. (Setting “L”...Data “0”. Setting “H”...Data “1”).

When ADRA0 to 2 = “111”, the device address A line is specified collectively, and when ADRB0 to 2 = “111”, the device address B line is specified

collectively.

Because up to 7 addresses can be specified for each of device address A and device address B, their combination allows the specification of up

to 49 addresses.

000

X X

X

SCL-I

Name

START

Device

ID

Device

address A

Device

address B

Device selection data

dvc_dat[7:0]

Control data

ctrl_dat[6:0]

Output address

END

Lighting data

light_dat[8:0]

Lighting

speed

Lighting

gradation

SDA-I

1

1

1

11

11

1

1

00

0

bit

1

234

5

6

7

8

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

Communication Format

Device ID

Device-specific ID (Fixed to “00” for this IC)

Device Address A

Specified with the ADRA0 to 2 terminals

Device Address B

Specified with the ADRB0 to 2 terminals

Control

Specifies control

(data saving / immediate reflection)

Output Address

Specifies the terminal to output

(Individual specification and collective specification are possible)

Lighting Speed

Specifies changing speed of free-running gradation control (32 levels)

Lighting Gradation

Specifies the brightness of lighting (16 levels)

Device selection data dvc_dat (7:0)

Device ID

Device Address A

Device Address B

0

0

ADRA2

ADRA1

ADRA0

ADRB2

ADRB1

ADRB0

Device Selection Data

Control Data

Lighting Data