
1996 Jan 08
36
Philips Semiconductors
Preliminary specification
Microcontroller for monitor OSD
and auto-sync applications
PCE84C882
12.4
Derivative Register 34
This register selects the 4 display modes; the active state of signal at the HSYNCN and VSYNCN inputs and the output
polarity of the FB and VOW0 to VOW2 outputs. It also enables/disables the OSD clock.
Table 25
Derivative Register 34
Table 26
Description of Derivative Register 34 bits
Table 27
Selection of Display Modes
7
6
5
4
3
2
1
0
S1
S0
Hp
Vp
Bp
EN
BIT
SYMBOL
S1
S0
Hp
DESCRIPTION
7
6
5
4
3
These two bits are reserved.
Display mode select bits; see Table 27.
HSYNCN signal polarity control bit. When Hp = 0, the active level of the signal at the
HSYNCN input is LOW; this is also the default state. When Hp = 1, the active level of
the signal at the HSYNCN input is HIGH. See Fig.16.
VSYNCN signal polarity control bit. When Vp = 0, the active level of the signal at the
VSYNCN input is LOW; this is also the default state. When Vp = 1, the active level of
the signal at the VSYNCN input is HIGH. See Fig.16.
Output polarity control bit for FB, VOW0, VOW1 and VOW2. When Bp = 1; these
outputs are active HIGH; this is also the default state. When Bp = 0; these outputs are
active LOW.
OSD clock enable/disable bit. When EN = 1; the OSD clock is enabled. When EN = 0;
the OSD clock is disabled.
2
Vp
1
Bp
0
EN
S1
S0
DISPLAY MODE
0
0
Mode 0: No background (superimpose) mode. The OSD characters are superimposed
on the monitor video signals. See Fig.27.
Mode 1: North shadowing mode. The characters’ shadows are generated as if a light
source was placed North of the character (see Fig.28). Character shadowing only
appears within the cell boundary. Consequently, if Row 18 contains a bit pattern then
North shadowing will not be shown on the screen (see Fig.20). The depth of shadow
displayed is dependent upon the character size; characters with sizes of 1H/1V; 1H/2V
and 1H/3V have a depth of shadow equivalent to 1 scan line whereas a character of
size 1H/4V has a depth of shadow equivalent to 2 scan lines. Examples of characters
with North shadowing, for the 4 character sizes, are shown in Fig.29.
Mode 2: Box shadowing mode. A background dot matrix of 12
×
18 bits surrounds the
character font; where there is no foreground dot a background dot is displayed (see
Fig.30).
Mode 3: Frame shadowing mode. A background colour fills the whole screen when no
bit patterns are being displayed (see Fig.31). 1 of 8 background colours can be selected
using Derivative Register 37; the default background colour is blue.
0
1
1
0
1
1