http://www.crystalfontz.com

email: sales@crystalfontz.com

Phone: (509) 291-3514

Fax:

(509) 291-3345

Crystalfontz America, Inc.

15611 East Washington Road

Valleyford, WA 99036

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The LCD display Module is built in a LSI controller, the controller has two 8-bit registers, an

instruction register (IR) and a data register (DR).

The IR stores instruction codes, such as display clear and cursor shift, and address information

for display data RAM (DDRAM) and character generator (CGRAM). The IR can only be written

from the MPU.

The DR temporarily stores data to be written or read from DDRAM or

CGRAM.

When address information is written into the IR, then data is stored into the DR from

DDRAM or CGRAM.

By the register selector (RS) signal, these two registers can be selected.

RS

R/W

Operation

0

0

IR write as an internal operation (display clear, etc.)

0

1

Read busy flag (DB7) and address counter (DB0 to DB7)

1

0

Write data to DDRAM or CGRAM (DR to DDRAM or CGRAM)

1

1

Read data from DDRAM or CGRAM (DDRAM or CGRAM to DR)

Busy Flag (BF)

When the busy flag is 1, the controller LSI is in the internal operation mode, and the next

instruction will not be accepted.

When RS=0 and R/W=1, the busy flag is output to DB7.

The

next instruction must be written after ensuring that the busy flag is 0.

Address Counter (AC)

The address counter (AC) assigns addresses to both DDRAM and CGRAM