Z90251 Datasheet, PDF (33/97 Pages) Zilog, Inc. – eZVision 200 Television Controllers with OSD

Z90255 ROM and Z90251 OTP
32 KB Television Controller with OSD
25
Horizontal Position Register
The Horizontal Position Register sets the horizontal start position of the OSD
(Table 7). The unit of measure for placement is the number of pixels from the left
of the display screen.
Table 10 Horizontal Position Register 02h:Bank A (HOR_POS)
Bit
7
6
5
4
3
2
1
0
R/W
Reset
R/W R/W R/W R/W R/W R/W R/W R/W
0
1
0
0
0
0
1
1
Note: R = Read W = Write X = Indeterminate
Register Field
Bit Position R/W Data Description
Progressive mode
Reserved
Horizontal position
7-------
-6------
5,4,3,2,1,0
R/W 0
1
R
W
R/W
Normal
Support progressive sync inputs
Return 1
No effect
Horizontal position control
When working with Progressive mode, fringing does not work
with 2X mode or double height mode, nor does Mesh work the
same way as in Interlace mode.
The value required for this register can be computed using the following equation:
HOR_POS = (H_POS - 1) / 4
HOR_POS represents the contents of bits 5,4,3,2,1,0 of the Horizontal
Position Register (HOR_POS). The default value is 3h. When the value is 3h, the
OSD is at the left-most OSD position on the screen.
H_POS is the number of pixels from the left of the screen to the OSD start position.
H_POS must be a positive integer with a minimum value of 5 incrementing by 4.
5.2 Second Color Feature
Second Color feature is the logical division of each column into two parts along
each row for changing foreground color. The number of each half-column is called
the Second Color Position.
PS001301-0800