Product specifications

VT8235 V-Link South Bridge
Revision 1.22 October 24, 2002 -22- Register Overview
Table 7. Registers
Legacy I/O Registers
Port
Master DMA Controller Registers Default Acc
00 Channel 0 Base & Current Address RW
01 Channel 0 Base & Current Count RW
02 Channel 1 Base & Current Address RW
03 Channel 1 Base & Current Count RW
04 Channel 2 Base & Current Address RW
05 Channel 2 Base & Current Count RW
06 Channel 3 Base & Current Address RW
07 Channel 3 Base & Current Count RW
08 Status / Command RW
09 Write Request
WO
0A Write Single Mask
WO
0B Write Mode
WO
0C Clear Byte Pointer FF
WO
0D Master Clear
WO
0E Clear Mask
WO
0F Read / Write Mask RW
Port
Master Interrupt Controller Regs Default Acc
20 Master Interrupt Control — *
21 Master Interrupt Mask — *
20 Master Interrupt Control Shadow —
RW
21 Master Interrupt Mask Shadow —
RW
* RW if shadow registers are disabled
Port
Timer/Counter Registers Default Acc
40 Timer / Counter 0 Count RW
41 Timer / Counter 1 Count RW
42 Timer / Counter 2 Count RW
43 Timer / Counter Control
WO
Port
Keyboard Controller Registers Default Acc
60 Keyboard Controller Data RW
61 Misc Functions & Speaker Control RW
64 Keyboard Ctrlr Command / Status RW
Port
CMOS / RTC / NMI Registers Default Acc
70 CMOS Memory Address & NMI Disa
WO
71 CMOS Memory Data (128 bytes) RW
74 CMOS Memory Address RW
75 CMOS Memory Data (256 bytes) RW
NMI Disable is port 70h (CMOS Memory Address) bit-7.
RTC control occurs via specific CMOS data locations (0-Dh).
Ports 74-75 may be used to access CMOS if the internal RTC
is disabled.
Legacy I/O Registers (continued)
Port
DMA Page Registers Default Acc
87 DMA Page – DMA Channel 0 RW
83 DMA Page – DMA Channel 1 RW
81 DMA Page – DMA Channel 2 RW
82 DMA Page – DMA Channel 3 RW
8F DMA Page – DMA Channel 4 RW
8B DMA Page – DMA Channel 5 RW
89 DMA Page – DMA Channel 6 RW
8A DMA Page – DMA Channel 7 RW
Port
System Control Registers Default Acc
92 System Control RW
Port
Slave Interrupt Controller Regs Default Acc
A0 Slave Interrupt Control — *
A1 Slave Interrupt Mask — *
A0 Slave Interrupt Control Shadow —
RW
A1 Slave Interrupt Mask Shadow —
RW
* RW accessible if shadow registers are disabled
Port
Slave DMA Controller Registers Default Acc
C0 Channel 0 Base & Current Address RW
C2 Channel 0 Base & Current Count RW
C4 Channel 1 Base & Current Address RW
C6 Channel 1 Base & Current Count RW
C8 Channel 2 Base & Current Address RW
CA Channel 2 Base & Current Count RW
CC Channel 3 Base & Current Address RW
CE Channel 3 Base & Current Count RW
D0 Status / Command RW
D2 Write Request
WO
D4 Write Single Mask
WO
D6 Write Mode
WO
D8 Clear Byte Pointer FF
WO
DA Master Clear
WO
DC Clear Mask
WO
DE Read / Write Mask RW