¡ Semiconductor

MSC7128-xx

12/27

FUNCTIONAL DESCRIPTION

Data Transfer Method and Command Write Method

A display control command or data is written by the 8-bit serial transfer method. The figure

below shows the write timing. When the CS pin is Low, data can be transferred. Data of 8 bits

in length is input to the DA pin sequentially starting with the LSB. (LSB first)

Data is shifted at the rising edge of a shift clock pulse which is input to the CP pin as shown in

the figure below. When 8-bit data is entered, an inner LOAD signal is automatically generated,

and data is written into the registers and RAM. Therefore, there is no need to input an external

LOAD signal.

If the CS pin is changed from Low to High, the serial transfer is inhibited, and data, which is

entered after the CS pin is changed from High to Low, is recognized in units of 8 bits.

The first 8 bits become the first byte, and the second 8 bits become the second byte and the next

8 bits become either the first byte or the second byte depending on the selected command.

CS

CP

DA

b0 b1 b2 b3 b4 b5 b6 b7

b0 b1 b2 b3 b4 b5 b6 b7

LSB

LSB

MSB

MSB

First Byte

Second Byte

Address Set

Lamp Test

Character Code Set

Display Duty Set

Number of Display Digits Set

No.

Command

0

1

2

3

4

b7

1

1

1

1

1

b6

0

1

0

0

0

b5

0

0

0

1

1

b4

0

0

1

0

1

b3

X

X

X

X

X

b2

X

X

X

X

X

b1

X

X

X

X

X

b0

X

X

X

X

X

b7

X

X

CU

X

X

b6

X

X

X

X

b5

X

X

X

X

b4

X

X

X

X

b3

X

b2

X

b1

X

b0

LT

First Byte

Second Byte

Command Type

*1 When character codes are to be continuously transferred, addresses are automatically

incremented (internally). Accordingly, neither the Address Set command nor the first byte

of the Character Code Set command are required to set the second and the following character

codes.

*2 X : Don’t care