FUNCTIONAL DESCRIPTION (continued)

After the falling edge on V-SYNC, the first strip

descriptor is read at the top of the current table of

descriptors at the address given by P[9:0] (see

DISPLAY CONTROL register).

If it is a spacing strip, SL[7:0] black or transparent

scan lines are displayed.

If it is a character strip, during CH[5:0] x (I + ZY)

scan lines (CH[5:0] given by the CHARACTER

HEIGHT register), the character codes are read at

the addresses starting from the 1

descriptor until a end of line character or the end of

the scan line.

The next descriptor is then read and the same proc-

ess is repeated until the next falling edgeon V-SYNC.

CSD FBK FL[1:0]

P8

P7

P8

DISPLAY CONTROL Register

TABLE OF THE

DESCRIPTORS

2nd CHARACTER

STRIP CODES

OTHER

TABLE OF

DESCRIPTORS

OTHER

(UDC for example)

1st CHARACTER

STRIP CODES

3rd CHARACTER

SRTIP CODES

OTHER

(CODES OR

DESCRIPTORS)

SPACING

ROW1

ROW2

SPACING

ROW3

SPACING

RAM CODE

AND DESCRIPTORS

V-SYNC

TOP SPACING STRIP

1st CHARACTER STRIP

2nd CHARACTER STRIP

3rd CHARACTER STRIP

SPACING STRIP

|

BOTTOM SPACING STRIP

SCREEN

Figure 7 : Relation between Screen/Address Page/Character Code in RAM

Slice 18 of the character n

°2

only for vertical shadowing

(not displayed).

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

123

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

456

36 Pixels (= 3 Characters)

Character Number

Character Number

ON THE SCREEN

(example for Character n

°5)

IN THE RAM

Slice 0

Slice 1

Slice 2

Slice 3

Slice 4

Slice 5

Slice 6

Slice 7

Slice 8

Slice 9

Slice 10

Slice 11

Slice 12

Slice 13

Slice 14

Slice 15

Slice 16

Slice 17

Slice 18

: 0x01

: 0x00

: 0x08

: 0x0c

: 0x0e

: 0x0f

: 0x0f

: 0x0f

: 0x0f

: 0x0e

: 0x0c

: 0x00

: 0x00

: 0x00

: 0x00

: 0x00

: 0x00

: 0x00

: 0x00

0xff =

0xff

0x7f

0x3f

0x1f

0x1f

0x1f

0x1e

0x1e

0x3c

0x3c

0x78

0x78

0xf1

0x00

0x00

0x00

0x00

0x00

Odd

Address

Even

Address

Figure 8 : User Definable Character

STV9422 - STV9424

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