M69000 Asiliant Technologies, M69000 Datasheet - Page 152

• Manufacturer Part Number: M69000
• Manufacturer: Asiliant Technologies

Specifications of M69000

• Lead Free Status / Rohs Status: Supplier Unconfirmed

GR06
read/write at I/O address 3CFh with index at address 3CEh set to 06h
7-4
3-2
Note:
1
0
&+,36
7
Reserved
Memory Map Mode
These 2 bits control the mapping of the frame buffer into the CPU address space as follows:
This function is both in standard VGA modes and in extended modes that do not provide linear
frame buffer access.
Chain Odd/Even
Graphics/Text Mode
69000 Databook
Miscellaneous Register
This bit provides the ability to alter the interpretation of address bit A0, so that it may be
used in selecting between the odd-numbered memory planes (planes 1 and 3) and the
even-numbered memory planes (planes 0 and 2).
0: A0 functions normally.
1: A0 is switched with a high order address bit, in terms of how it is used in address
decoding. The result is that A0 is used to determine which memory plane is being
accessed:
0: Selects text mode.
1: Selects graphics mode.
6
Bits
3 2
0 0
0 1
1 0
1 1
Reserved
A0 = 0: planes 0 and 2
A0 = 1: planes 1 and 3
Frame Buffer Address Range
5
Subject to Change Without Notice
A0000h - BFFFFh
A0000h - AFFFFh
B8000h - BFFFFh
B0000h - B7FFFh
Graphics Controller Registers
4
Memory Map Mode
3
2
Chain Odd/
Even
Revision 1.3 8/31/98
1
Text Mode
Graphics /
0
11-9