B69000 Asiliant Technologies, B69000 Datasheet - Page 125

• Manufacturer Part Number: B69000
• Manufacturer: Asiliant Technologies

Specifications of B69000

• Lead Free Status / Rohs Status: Supplier Unconfirmed

9-32
CR38
read/write at I/O address 3B5h/3D5h with index at address 3B4h/3D4h set to 38h
7-1
0
&+,36
7
Reserved
These bits should always be written with the value of 0.
Horizontal Total Bit 8
The horizontal total is an 8-bit or 9-bit value that specifies the total length of a scanline. This
includes both the part of the scanline that is within the active display area and the part that is outside
of it.
69000 Databook
Extended Horizontal Total Register
In standard VGA modes, where bit 0 of the I/O Control Register (XR09) is set to 0, the
horizontal total is specified with an 8-bit value. All 8 bits of the horizontal total are supplied
by bits 7-0 of the Horizontal Total Register (CR00). In standard VGA modes, this bit is not
used.
In extended modes, where bit 0 of the I/O Control Register (XR09) is set to 1, the horizontal
total is specified with a 9-bit value. The 8 least significant bits of this value are supplied by
bits 7-0 of the Horizontal Total Register (CR00), and the most significant bit is supplied by
this bit of this register.
This 8-bit or 9-bit value should be programmed to equal the total number of character
clocks within the total length of a scanline minus 5.
Note: For NTSC/PAL output support, CR79 can be used to add a programmable number
of pixel clocks (as opposed to character clocks) to the horizontal total, permitting the
horizontal total to be specified with greater precision.
6
5
Subject to Change Without Notice
CRT Controller Registers
(0000:000)
Reserved
4
3
2
Revision 1.3 8/31/98
1
Hor Total
Bit 8
(0)
0