w83c553f Winbond Electronics Corp America, w83c553f Datasheet - Page 68

• Manufacturer Part Number: w83c553f
• Description: System I/o Controller With Pci Arbiter
• Manufacturer: Winbond Electronics Corp America

W83C553F
ISA-to-PCI Memory Hole Start Address Register (default = 00h)
Type:
Bit Description:
ISA-to-PCI Memory Hole Size Register (default = 00h)
Type:
Bit Description:
WINBOND SYSTEMS LABORATORY
Bits [7:0]:
Bit 7:
Bits [6:0]:
Read/Write
IPAHA. Memory Hole Start Address. These 8 bits specify the 8 most significant bits of the ISA
address: LA[23:16].
Read/Write
IPAHE. Memory Hole Enable. When this bit is set to "1", access to the memory hole will not be
forwarded to the PCI bus. When this bit is reset to "0", access to the hole will be forwarded to
the PCI bus. The default value of this bit after a chip reset is "0".
IPAHS. Memory Hole Size. This field specifies the sizes of the memory hole according to the
following list:
All other combinations are reserved.
LA23
Bit 6
Bit 7
0
0
0
0
0
0
0
1
Bit 5
LA22
0
0
0
0
0
0
1
1
Bit 6
Bit 4
LA21
0
0
0
0
0
1
1
1
Bit 5
Bit 3
0
0
0
0
1
1
1
1
LA20
Bit 4
Bit 2
0
0
0
1
1
1
1
1
LA19
Bit 3
Bit 1
0
0
1
1
1
1
1
1
LA18
Bit 2
Bit 0
0
1
1
1
1
1
1
1
LA17
Bit 1
= 64 KBytes
= 125 KBytes
= 256 KBytes
= 512 KBytes
= 1 MBytes
= 2 MBytes
= 4 MBytes
= 8 MBytes
SA16
Bit 0
Electrical Specifications
65