
ON-SCREEN DISPLAY
S3C880A/F880A
13-10
FADE-IN AND FADE-OUT CONTROL REGISTER (FADECON)
The OSD block lets you program fade-in and fade-out displays. A fade-in display is one in which a character
matrix is displayed incrementally until the complete character "appears". A fade-out display shows the complete
character matrix first and then decrements the matrix line-by-line until the character "disappears" from the
display field.
The address of the character display (and the specific line) to be faded-in or faded-out is selected by writing bit
values into the CHACON and FADECON registers. Bits 3–0 in the CHACON register specify the 4-bit video RAM
address of one of the twelve rows (0–11) of the fade display. Bits 0–4 in the FADECON register specify the 5-bit
line address within the selected row.
Fade direction is controlled by FADECON.5. There are two choices of fade direction: before (FADECON.5 = "0")
and after (FADECON.5 = "1"). When you select fade before, the character matrix is faded starting with line 0.
When you select fade after, the matrix is faded starting with inter-row space line 6. (The inter = row space line 6
start position is only a suggestion, however, as the fade interval is assignable by software.) To enable the fade
function, you should set FADECON.6 to "1". (FADECON.7 is not used).
NOTE
To avoid confusion in determining fade row and line addresses in the CHACON and FADECON
registers, please note that line is a horizontal value that encompasses the entire character display field
while row is a horizontal value for the character display matrix.
OSD Fade Control Register (FADECON)
F1H, Set 1, Bank 1, R/W
LSB
MSB
.7
.6
.5
.4
.3
.2
.1
.0
Fade function enable bit:
0 = Fade disable
1 = Fade enable
Fade row address selection bits:
00000 = Line 0
00001 = Line 1
00010 = Line 2
00011 = Line 3
00100 = Line 4
00101 = Line 5
00110 = Line 6
00111 = Line 7
01000 = Line 8
01001 = Line 9
01010 = Line 10
01011 = Line 11
01100 = Line 12
01101 = Line 13
01110 = Line 14
01111 = Line 15
10000 = Line 16
10001 = Line 17
10010 = Inter-row space Line 0 (1H)
10011 = Inter-row space Line 1 (2H)
10100 = Inter-row space Line 2 (3H)
10101 = Inter-row space Line 3 (4H)
10110 = Inter-row space Line 4 (5H)
10111 = Inter-row space Line 5 (6H)
11000 = Inter-row space Line 6 (7H)
11001-11111 = Not used
Not used
Fade direction selection bit:
0 = Fade before matrix
1 = Fade after matrix
Figure 13-6. OSD Fade Control Register (FADECON)