M69030 Asiliant Technologies, M69030 Datasheet - Page 105

• Manufacturer Part Number: M69030
• Manufacturer: Asiliant Technologies

Specifications of M69030

• Operating Temperature (min): 0C
• Operating Temperature Classification: Commercial
• Operating Temperature (max): 70C
• Rad Hardened: No
• Lead Free Status / Rohs Status: Supplier Unconfirmed

CR00
read/write at I/O address 3B5h/3D5h with index at address 3B4h/3D4h set to 00h
shadowed for pipelines A and B
7-0
CR01
read/write at I/O address 3B5h/3D5h with index at 3B4h/3D4h set to 01h
shadowed for pipelines A and B
7-0
`efmp
A
B
A
B

Horizontal Total
Horizontal Display Enable End
69030 Databook
7
7
Horizontal Total Register
Horizontal Display Enable End Register
These bits provide either all 8 bits of an 8-bit value or the least significant 8 bits of a 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.
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, 8 bits of which are supplied by this register.
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 the vertical total are
supplied by the 8 bits of this register. The most significant bit is supplied by bit 0 of the
Extended Horizontal Total Register (CR38).
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.
This register is used to specify the end of the part of the scanline that is within the active
display area relative to its beginning. In other words, this is the horizontal width of the active
display area.
This register should be programmed with a value equal to the number of character clocks
that occur within the part of a scanline that is within the active display area minus 1.
6
6
5
5
CRT Controller Registers
Horizontal Display Enable End
Horizontal Display Enable End
Horizontal Total
Horizontal Total
4
4
3
3
2
2
Revision 1.3 11/24/99
1
1
0
0
9-3