2010-04-13

8

SCDQ5541P/Q/R, SCDQ5542P/Q/R, SCDQ5543P/Q/R, SCDQ5544P/Q/R

SCDQ Block Diagram

The following explains how to format the serial data to be loaded into the display. The user supplies a string of bit mapped decoded char-

acters. The contents of this string is shown in Figure „Loading Serial Character Data A“ (page 8). Figure „Loading Serial Character

Data B“ (page 8) shows that each character consists of six 8 bit words. The first word encodes the display character location and the suc-

ceeding five bytes are row data. The row data represents the status (On, Off) of individual column LEDs. Figure „Loading Serial Character

Data C“ (page 8) shows that each 8 bit word is formatted to include a three bit Operational Code (OPCODE) defined by bits D7–D5 and

five bits (D4–D0) representing Column Data, Character Address, or Control Word Data.

Figure „Loading Serial Character Data D“ (page 8) shows the sequence for loading the bytes of data. Bringing the LOAD line low enables

the serial register to accept data. The shift action occurs on the low to high transition of the serial data clock (SDCLK). The least significant

bit (D0) is loaded first. After eight clock pulses the LOAD line is brought high. With this transition the OPCODE is decoded. The decoded

OPCODE directs D4–D0 to be latched in the Character Address register, stored in the RAM as Column data, or latched in the Control

Word register. The control IC requires a minimum 600 ns delay between successive byte loads.

Loading Serial Character Data

IDBD5061

&

3

5

3

Display Multiplexer

20 x 5 bit

Dual Port Ram

Power Down

Brightness

Lamp Test

Column Logic

& Driver

20

& Driver

Row Decoder

5

4 - 5 x 5

Characters

Oscillator

& Timing

Counter Chain

LOAD

SDATA

SDCLK

20

IDTC5043

D0

0

Character

0

D1

0

D2

0

D3

0

D4

Address

Opcode

D5

D7

1

0

D6

1

TBL

600 ns

min.

Column Data

C4

D0

C3

D1

C2

D2

D4

C0

C1

D3

Opcode

D5

0

D6

0

0

D7

min.

600 ns

TBL

D

Character

Address 0

Row 0

Column Data

Row 1

Column Data

Row 2

Column Data

Row 3

Column Data

Row 4

Column Data

C

B

C

A

Character 0

Character 1

Character 2

Character 3

B

LOAD

SDCLK

DATA

D0

D1

D2

D3

D4

D5

D6

D7

TBL

DD

D