Z90251 Datasheet, PDF (58/97 Pages) Zilog, Inc. – eZVision 200 Television Controllers with OSD

Z90255 ROM and Z90251 OTP
32 KB Television Controller with OSD
50
allowing 2286 µs to program the next row. Additional programming time is
available with inter-row spacing. VRAM is updated during that time.
If the program has too much to display, black lines appear at the top of the screen.
The HV Interrupt Status Register (Table 34) keeps track of the type of interrupt
issued, horizontal or vertical.
Table 34 HV Interrupt Status Register 07h: Bank C (INT_ST)
Bit
7
6
5
4
3
2
1
0
R/W
R/W R/W R/W R/W R/W R/W R/W R/W
Reset
0
0
0
0
0
0
0
0
Note: R = Read W = Write X = Indeterminate
Bit/
Field
Bit
Position R/W Value Description
Fringe Color Selection 7
R/W 0 Select Character Background Color
1 Select Fringe Color RGB*
Fringe Color
6, 5, 4 R/W
Defines Fringe Color RGB
Palette Mode
3
R/W 0 Normal Mode
1 Color Palette Mode
Horizontal Interrupt 2
Enable
R/W 0 No Horizontal Interrupt
1 Enable Horizontal Interrupt
Vertical Interrupt
1
R 0 No Vertical Interrupt
1 Vertical Interrupt
W 0 No Effect
1 Reset Vertical Interrupt Flag
Horizontal Interrupt 0
R 0 No Horizontal Interrupt
1 Horizontal Interrupt
W 0 No Effect
1 Reset Horizontal Interrupt Flag
Note: The fringing feature is not available in Progressive Mode.
Bit 7, Fringe Color Selection, sets the fringe color to the background color or to a
Red, Green, and Blue color specified in bits 6,5,4.
Bit 3, Palette Mode, sets color to Normal or VRAM Mode. When the value is 0
(Normal Mode), the color attribute of a row is controlled by values in the
ROW_ATTR register which is mapped in VRAM, but the Color Palette Selection Bits
PS001301-0800