B69000 Asiliant Technologies, B69000 Datasheet - Page 105

• Manufacturer Part Number: B69000
• Manufacturer: Asiliant Technologies

Specifications of B69000

• Lead Free Status / Rohs Status: Supplier Unconfirmed

9-12
CR08
read/write at I/O address 3B5h/3D5h with index at address 3B4h/3D4h set to 08h
7
6-5
4-0
&+,36
Reserved
7
Reserved
Leftward Horizontal Pixel Shift
Bits 6 and 5 of this register hold a 2-bit value that selects number of bytes (up to 3) by which the
image is shifted horizontally to the left on the screen. This function is available in both text and
graphics modes.
In text modes with a 9-pixel wide character box, the image can be shifted up to 27 pixels to the left,
in increments of 9 pixels.
In text modes with an 8-pixel wide character box, and in all standard VGA graphics modes, the
image can be shifted up to 24 pixels to the left in increments of 8 pixels.
The image can be shifted still further, in increments of individual pixels, through the use of bits 3-0
of the Horizontal Pixel Panning Register (AR13).
Starting Row Scan Count
69000 Databook
Preset Row Scan Register
Note: In the VGA standard this is called the ‘Byte Panning’ bit.
These 5 bits specify which horizontal line of pixels within the character boxes of the
characters used on the top-most row of text on the display will be used as the top-most
scanline. The horizontal lines of pixels of a character box are numbered from top to bottom,
with the top-most line of pixels being number 0. If a horizontal line of these character boxes
other than the top-most line is specified, then the horizontal lines of the character box above
the specified line of the character box will not be displayed as part of the top-most row of
text characters on the display. Normally the value specified by these 5 bits should be 0, so
that all of the horizontal lines of pixels within these character boxes will be displayed in the
top-most row of text, ensuring that the characters in the top-most row of text do not look as
though they have been cut off at the top.
Left Hor Pixel Shift
6
5
Subject to Change Without Notice
0 0
0 1
1 0
1 1
6 5
Bit
CRT Controller Registers
Number of Pixels Shifted
4
9-Pixel
Text
18
27
0
9
8-Pixel Text
& Graphics
3
Starting Row Scan Count
16
24
0
8
2
Revision 1.3 8/31/98
1
0