¡ Semiconductor

MSM9005-xx

10/30

FEDL9005-03

FUNCTIONAL DESCRIPTION

General Description of Block Diagram

1. Address Pointer

An address pointer is a 5-bit counter which assigns the write destination or read destination

address of CGA RAM and AB RAM, and the write destination address of CHB RAM and ABB

RAM. The value of the address pointer can be set by the LPA command. The value of the

address pointer is automatically incremented by 1 after executing the AINC and CHB

commands, or after transferring input display data.

2. Character Generator Address RAM (CGA RAM)

The character generator address RAM stores 8-bit character codes of the character generator

ROM. A maximum of thirteen 8-bit character codes can be stored.

3. Arbitrator RAM (AB RAM)

The arbitrator RAM stores the lighting data of the arbitrator. Lighting data is stored in 5 dot

units, and a maximum of 65 dots of lighting data can be stored.

4. Character Blink RAM (CHB RAM)

The character blink RAM stores character blink data. A maximum of 13 characters of blink

data can be stored.

5. Arbitrator Blink RAM (ABB RAM)

The arbitrator blink RAM stores blink data of the arbitrator. Blink data is stored in 5 dot units,

and a maximum of 65 dots of blink data can be stored.

6. Character Generator ROM (CG ROM)

The character generator ROM generates character patterns with 5 ¥ 7 dots. This ROM can store

a maximum of 256 types of characters, numerics, and symbols.

When an 8-bit character code of CG ROM is written to CGA RAM, character patterns with

5 ¥ 7 dots corresponding to 8-bit character code are displayed at the LCD display position

corresponding to the CGA RAM address.

Relationship between display screen, LCD output and memory address

10000b

00000b

10001b

00001b

10010b

00010b

10011b

00011b

10100b

00100b

10101b

00101b

10110b

00110b

10111b

00111b

11000b

01000b

11001b

01001b

11010b

01010b

11011b

01011b

11100b

01100b

S1

S5 S6

S10 S11

S15 S16

S20 S21

S25 S26

S30 S31

S35 S36

S40 S41

S45 S46

S50 S51

S55 S56

S60 S61

S65

C2

C3

C4

C5

C6

C7

C8

C1

Arbitrator

Character

Arbitrator

Character

Screen

RAM

Address

map