SCE5740, SCE5741, SCE5742, SCE5743, SCE5744, SCE5745

2006-03-30

9

Row Strobing

Multiplexer and Display Driver

The four characters are row multiplexed with RAM resident column

data. The strobe rate is established by the internal or external

MUX Clock rate. The MUX Clock frequency is divided by a 448

counter chain. This results in a typical strobe rate of 768 Hz. By

pulling the Clock SEL line low, the display can be operated from an

external MUX Clock. The external clock is attached to the CLK I/O

connection (pin 8). The maximum external MUX Clock frequency

should be limited to 3 MHz.

When a high speed external clock is used the frequency can be

further divided down by 16 by using the built in prescaler. In the

control word format data bit D4 is set high (D4=1). It is not recom-

mended to use the prescaler with the internal clock.

An asynchronous hardware Reset (pin 6) is also provided. Bring-

ing this pin low will clear the Character Address Register, Control

Word Register, RAM, and blanks the display. This action leaves the

display set at Character Address 0, and the Brightness Level set at

100%.

The user can activate four Control functions. These include: LED

Brightness Level, IC Power Down, Prescaler, or Display Clear.

OPCODEs and six bit words are used to initiate these functions.

The OPCODEs and Control Words for the Character Address and

Loading Column Data are shown in Tables „Load Character

Address“ (page 10) and „Load Column Data“ (page 10).

Control Word Format

0

4

5

6

Columns

12 3 4

Load

Row

Load Row 0

1

2

3

0

Columns

01 23 4

Columns

01 2 34

Load Row 1

Load Row 2

Load Row 5

Columns

Columns

01 2 3 40

Columns

12 3 4

01

Load Row 4

Load Row 3

Columns

IDXX5184

23 4

01 2 34

Load Row 6

6

5

3

4

2

0

1

6

5

3

4

2

0

1

6

5

3

4

2

0

1

6

5

3

4

2

0

1

6

5

3

4

2

0

1

6

5

3

4

2

0

1

Basic Instruction Set

Instruction

Opcode

Address/Data

Comments

LCD

000

D4

D3

D2

D1

D0

Load Column Data

LDA

101

X

X

A2

A1

A0

Load Digit Address

SCL

110

PS

B3

B2

B1

B0

Software Clear

LCWD

111

PS

B3

B2

B1

B0

Load Control Word Data

IDCW5162

D7

1

D6

1

D5

1

D4

PS

D3

B3

D2

B2

D1

B1

D0

B0

6.6%

0

0

1

1

B2

100%

27%

40%

20%

13%

53%

0

0

1

Brightness

B1

0

B0

0

0

1

1

01

0

010

10

1

11

1

Blank Display &

Power Down

0

1

Full

Reduce to 12.5%

Pre-Scalar

MUX Clock/16

0

No Divide

1

by 16

PS

B3 Peak Current