Display Data RAM (DDRAM)

The Display data RAM (DDRAM) stores display data represented in 8-bit character codes. Its extended capacity is

80

´8 bits or 80 characters. The area in the DDRAM that is not used for display can be used as general data RAM. Refer

to DDRAM address table for the relationships between DDRAM address and positions on the VFD.

The DDRAM address (ADD) is set in the address counter (AC) as hexadecimal.

DDRAM Address Table

High Order Bits

Low Order Bits

AC6

AC5

AC4

AC3

AC2

AC1

AC0

Hexadecimal

Hexadecimal

Example: DDRAM address

²3FH²

0111111

3F

Display Position

(Digit)

123456

79

80

DDRAM Address

00

01

02

03

04

05

4E

4F

(Hexadecimal)

When there are fewer than 80 display characters, the display begins at the head position. For example, if using only

one HT16514, 24 characters are displayed. When display shift operation is performed, the DDRAMaddress shifts as

shown in the following table.

Example: 1-line by 24-character Display Table

Display Position

(Digit)

123456

23

24

DDRAM Address

00

01

02

03

04

05

16

17

(Hexadecimal)

For Shift Left

01

02

03

04

05

06

17

18

For Shift Right

4F

00

01

02

03

04

15

16

HT16514

Rev. 1.00

21

October 4, 2006