Product specifications

VT8235 V-Link South Bridge
Revision 1.22 October 24, 2002 -21- Register Overview
REGISTERS
Register Overview
The following tables summarize the configuration and I/O
registers of the VT8235. These tables also document the
power-on default value (“Default”) and access type (“Acc”)
for each register. Access type definitions used are RW
(Read/Write), RO (Read/Only), “—” for reserved / used
(essentially the same as RO), and RWC (or just WC) (Read /
Write 1’s to Clear individual bits). Registers indicated as RW
may have some read/only bits that always read back a fixed
value (usually 0 if unused); registers designated as RWC or
WC may have some read-only or read write bits (see
individual register descriptions for details).
Detailed register descriptions are provided in the following
section of this document. All offset and default values are
shown in hexadecimal unless otherwise indicated
Table 4. Memory Mapped Registers
FEC00000 APIC Index (8-bit)
FEC00010 APIC Data (32-bit)
FEC00020 APIC IRQ Pin Assertion (8-bit)
FEC00040 APIC EOI (8-bit)
“APIC” = “Advanced Programmable Interrupt Controller”
Table 5. Function Summary
Bus Device Func Device ID Function
0 16 (10h) 0 3038h USB 1.1 UHCI Ports 0-1
0 16 (10h) 1 3038h USB 1.1 UHCI Ports 2-3
0 16 (10h) 2 3038h USB 1.1 UHCI Ports 4-5
0 16 (10h) 3 3038h USB 2.0 EHCI Ports 0-5
0 17 (11h) 0 3074h Bus Control & Power Mgmt
0 17 (11h) 1 0571h IDE Controller
0 17 (11h) 5 3059h AC97 Audio Codec Controller
0 17 (11h) 6 3068h MC97 Modem Codec Ctrlr
0 18 (12h) 0 3043h VIA LAN Controller
Table 6. System I/O Map
Port Function Actual Port Decoding
00-1F Master DMA Controller 0000 0000 000x nnnn
20-3F Master Interrupt Controller 0000 0000 001x xxxn
40-5F Timer / Counter 0000 0000 010x xxnn
60-6F Keyboard Controller 0000 0000 0110 xnxn
(60h) KBC Data 0000 0000 0110 x0x0
(61h) Misc Functions & Spkr Ctrl 0000 0000 0110 xxx1
(64h) KBC Command / Status 0000 0000 0110 x1x0
70-77 RTC/CMOS/NMI-Disable 0000 0000 0111 0nnn
78-7F -available for system use- 0000 0000 0111 1xxx
80 -reserved- (debug port) 0000 0000 1000 0000
81-8F DMA Page Registers 0000 0000 1000 nnnn
90-91 -available for system use- 0000 0000 1001 000x
92 System Control 0000 0000 1001 0010
93-9F -available for system use- 0000 0000 1001 nnnn
A0-BF Slave Interrupt Controller 0000 0000 101x xxxn
C0-DF Slave DMA Controller 0000 0000 110n nnnx
E0-FF -available for system use- 0000 0000 111x xxxx
100-CF7 -available for system use*
CF8-CFB PCI Configuration Address 0000 1100 1111 10xx
CFC-CFF PCI Configuration Data 0000 1100 1111 11xx
D00-FFFF -available for system use-