Z90251 Datasheet, PDF (44/97 Pages) Zilog, Inc. – eZVision 200 Television Controllers with OSD

Z90255 ROM and Z90251 OTP
32 KB Television Controller with OSD
36
5.5 Inter-Row Spacing
Inter-Row Spacing can be from 0 to 15 horizontal scan line (HL). A setting of 0
HL is called Continuous Row Display. A horizontal interrupt is generated at the
start of each row. Software must program the spacing between the current row
and the next row during the current horizontal interrrupt.
The time required to process a row must not exceed the display time of the row.
Refer to Table 20.
Table 20 Row Space Register 04h: BankA (ROW_SPACE)
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
Fade On/Off
7
R/W 0 Fade feature disabled
1 Fade feature enabled
Fade Direction
6
R/W 0 Fade area below the defined fade
position
1 Fade area above the defined
fade position
Halftone Effect Output 5, 4
R/W
Delay On P20
Works with bit 7 in MC_Reg
Inter-Row Space
3, 2, 1, 0 R/W
Inter row spacing
Bit 7, Fade ON/OFF, disables or enables the fade effect.
Bit 6, Fade Direction, controls the direction of the fade effect. When Fade
Direction is set to 0, the bottom of the TV screen is faded out. Fading occurs
beginning with the row number set in FADE_POS1 (3,2,1,0) and the scan line
number set in FADE_POS2 (4,3,2,1,0). When the Fade Direction is set to 1,
the top of the screen is faded out.
Bits 5 and 4, Halftone Effect Delay on P20, work with MC_REG (7).
Bits 3, 2, 1, and 0, Inter-Row Space, specify the number of HL to add between
displayed rows.
PS001301-0800