Product specifications

VT8235 V-Link South Bridge
Revision 1.22 October 24, 2002 -70- Device 17 Function 0 Bus Control Registers
ISA Decoding Control
Offset 6C – ISA Positive Decoding Control 1..................RW
7 On-Board I/O (Ports 00-FFh) Positive Decoding
0 Disable .................................................. default
1 Enable
6 Microsoft-Sound System I/O Port Positive
Decoding
0 Disable .................................................. default
1 Enable (bits 5-4 determine the decode range)
5-4 Microsoft Sound System I/O Decode Range
00 0530h-0537h ......................................... default
01 0604h-060Bh
10 0E80-0E87h
11 0F40h-0F47h
3 Internal APIC Positive Decoding
0 Disable .................................................. default
1 Enable
2 BIOS ROM Positive Decoding
0 Disable .................................................. default
1 Enable
1 Internal PCS1# Positive Decoding
0 Disable .................................................. default
1 Enable
0 Internal PCS0# Positive Decoding
0 Disable .................................................. default
1 Enable
Offset 6D – ISA Positive Decoding Control 2..................RW
7 FDC Positive Decoding
0 Disable .................................................. default
1 Enable
6 LPT Positive Decoding
0 Disable .................................................. default
1 Enable
5-4 LPT Decode Range
00 3BCh-3BFh, 7BCh-7BEh...................... default
01 378h-37Fh, 778h-77Ah
10 278h-27Fh, 678h-67Ah
11 -reserved-
3 Game Port Positive Decoding
0 Disable .................................................. default
1 Enable
2 MIDI Positive Decoding
0 Disable .................................................. default
1 Enable
1-0 MIDI Decode Range
00 300-303h ............................................... default
01 310-313h
10 320-323h
11 330-333h
Offset 6E – ISA Positive Decoding Control 3 ................. RW
7 COM Port B Positive Decoding
0 Disable...................................................default
1 Enable
6-4 COM-Port B Decode Range
000 3F8h-3FFh (COM1)............................default
001 2F8h-2FFh (COM2)
010 220h-227h
011 228h-22Fh
100 238h-23Fh
101 2E8h-2EFh (COM4)
110 338h-33Fh
111 3E8h-3EFh (COM3)
3 COM Port A Positive Decoding
0 Disable...................................................default
1 Enable
2-0 COM-Port A Decode Range
000 3F8h-3FFh (COM1)............................default
001 2F8h-2FFh (COM2)
010 220h-227h
011 228h-22Fh
100 238h-23Fh
101 2E8h-2EFh (COM4)
110 338h-33Fh
111 3E8h-3EFh (COM3)
Offset 6F – ISA Positive Decoding Control 4 ................. RW
7-6 Reserved ........................................always reads 0
5 PCS2# and PCS3# Positive Decoding
0 Disable...................................................default
1 Enable
4 I/O Port 0CF9h Positive Decoding
0 Disable...................................................default
1 Enable
3 FDC Decoding Range
0 Primary ..................................................default
1 Secondary
2 Sound Blaster Positive Decoding
0 Disable...................................................default
1 Enable
1-0 Sound Blaster Decode Range
00 220-233h................................................default
01 240-253h
10 260-273h
11 280-293h