TOPWAY

LCD Module User Manual

LM3033CDW-0B

www.topwaysz.com

Document Name: LM3033CDW-0B-Manual-Rev0.1.DOC

Page: 8 of 13

4. Function Specifications

4.1

Resetting the LCD module

The LCD module should be initialized by setting /RST terminal at low level when turning the

power on. See the reset timing section for details.

The initialized status is as follow:

Functions

Initialized Status

ENTER MODE SET

I/D=1

cursor move to right

S=0

DDRAM address counter (AC) plus 1

DISPLAY STATUS

D=0

display = OFF

C=0

cursor = OFF

B=0

cursor position blink = OFF

FUNCTION SET

DL=1

8bit Interface

RE=0

Basic Instruction Set

SCROLL OR RAM ADDR. SELECT

SR=0

CGRAM address access is enabled

REVERSE

R1=0, R0=0

First line normal

EXTENDED FUNCTION SET

G=0

Graphic Display OFF

4.2

Using Parallel interface

When PSB=H, the LCD module is in parallel interface mode. 8-bit or 4-bit bus interface could

be selected by FUNCTION SET instruction DL bit.

In 4-bit bus interface, every 8-bit instruction/data is separated into two parts. First, transfer

the higher 4-bit (D7~D4). Then transfer the lower 4-bit (D3~D0). They are transferred via

DB7~DB4 terminals, where DB3~DB0 are not in used (leave open or pull high)

4.3

Using Serial interface

When PSB=L, the LCD module is in serial interface mode (write only).

In this mode, CS pin should be used. CS=H, enable the data transfer. CS=L, reset the serial

data counter, terminate the data transition and clear the data buffer.

As the controller IC have no instruction buffer area, it must wait for the previous instruction to

finish before sending the next one. Thus transferring multiple instruction/data, execution time

must be considered.

Starting a transmission, a start byte is required. It consists 5 consecutive “1” follow with a “0”,

a RS bit (Register Select bit) and a “0”.

Then the 8bit instruction/data should be separated into 2 groups. First group is DB7 to DB4,

followed by 4 consecutive “0”. The second group is DB3 to DB0 with 4 consecutive “0”.

See the Data Sequence Diagram for details.

Data Sequence Diagram (Serial Mode)