M69030 Asiliant Technologies, M69030 Datasheet - Page 137

• 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

CR38
read/write at I/O address 3B5h/3D5h with index at address 3B4h/3D4h set to 38h
shadowed for pipelines A and B
7-1
0
`efmp
A
B

Reserved
Horizontal Total Bit 8
69030 Databook
7
Extended Horizontal Total Register
These bits should always be written with the value of 0.
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.
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
CRT Controller Registers
(0000:000)
(0000:000)
Reserved
Reserved
4
3
2
Revision 1.3 11/24/99
1
Hor Total
Hor Total
Bit 8
Bit 8
(0)
(0)
0
9-35