M69000 Asiliant Technologies, M69000 Datasheet - Page 100

• Manufacturer Part Number: M69000
• Manufacturer: Asiliant Technologies

Specifications of M69000

• Lead Free Status / Rohs Status: Supplier Unconfirmed

CR06
read/write at I/O address 3B5h/3D5h with index at address 3B4h/3D4h set to 06h
7-0
&+,36
7
Vertical Total Bits
These bits provide the 8 least significant bits of either a 10-bit or 12-bit value that specifies the total
number of scanlines. This includes the scanlines both inside and outside of the active display area.
In standard VGA modes, where bit 0 of the I/O Control Register (XR09) is set to 0, the vertical total
is specified with a 10-bit value. The 8 least significant bits of the vertical total are supplied by these
8 bits of this register, and the 2 most significant bits are supplied by bits 5 and 0 of the Overflow
Register (CR07).
In extended modes, where bit 0 of the I/O Control Register (XR09) is set to 1, the vertical total is
specified with a 12-bit value. The 8 least significant bits of the vertical total are supplied by the 8
bits of this register (CR06). The 4 most significant bits are supplied by bits 3-0 of the Extended
Vertical Total Register (CR30).
This 10-bit or 12-bit value should be programmed to equal the total number of scanlines minus 2.
69000 Databook
Vertical Total Register
6
5
Subject to Change Without Notice
CRT Controller Registers
Vertical Total Bits 7-0
4
3
2
Revision 1.3 8/31/98
1
0
9-7