
VT8231
Preliminary Revision 0.8
October 29, 1999
-
51-
Register Descriptions - Super-I/O I/O Ports
7HFKQRORJLHV,QF
:H &RQQHFW
Parallel Port Registers
These registers are located at I/O ports which are offsets from
“
LPTBase
”
(index C6h of the Super-I/O configuration
registers). LPTBase is typically set to allow these ports to be
accessed at the standard parallel port address range of 378-
37Fh.
Port LPTBase+0
–
Parallel Port Data ............................. RW
7-0
Parallel Port Data
Port LPTBase+1
–
Parallel Port Status ........................... RO
7
BUSY#
0
Printer busy, offline, or error
1
Printer not busy
6
ACK#
0
Data transfer to printer complete
1
Data transfer to printer in progress
5
PE
0
Paper available
1
No paper available
4
SLCT
0
Printer offline
1
Printer online
3
ERROR#
0
Printer error
1
Printer OK
2-0
Reserved
...................................always read 1 bits
Port LPTBase+2
–
Parallel Port Control ........................ RW
7-5
Undefined
................................. always read back 1
4
Hardware Interrupt
0
Disable ...................................................default
1
Enable
3
Printer Select
0
Deselect printer ......................................default
1
Select printer
2
Printer Initialize
0
Initialize Printer......................................default
1
Allow printer to operate normally
1
Automatic Line Feed
0
Host handles line feeds...........................default
1
Printer does automatic line feeds
0
Strobe
0
No data transfer......................................default
1
Transfer data to printer
Port LPTBase+3
–
Parallel Port EPP Address............... RW
Port LPTBase+4
–
Parallel Port EPP Data Port 0 ........ RW
Port LPTBase+5
–
Parallel Port EPP Data Port 1 ........ RW
Port LPTBase+6
–
Parallel Port EPP Data Port 2 ........ RW
Port LPTBase+7
–
Parallel Port EPP Data Port 3 ........ RW
Port LPTBase+400h
–
Parallel Port ECP Data / Cfg A RW
Port LPTBase+401h
–
Parallel Port ECP Config B ...... RW
Port LPTBase+401h
–
Parallel Port ECP Extd Ctrl ..... RW