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PIO-D144 User’s Manual
Version: 2.1 Date: 1999/10 Page 27
3.3 The I/O Address Map
The I/O address of PIO/PISO series card is automatically assigned by
the main board ROM BIOS. The I/O address can also be re-assigned by user.
It is strongly recommended not to change the I/O address by user. The
Plug&Play BIOS will assign proper I/O address to each PIO/PISO series
card very well. The I/O address of PIO-D144 are given as follows:
Address
Read
Write
WBase+0
RESET\ control register
Same
WBase+2
Aux control register
Same
WBase+3
Aux data register
Same
WBase+5
INT mask control register
Same
WBase+7
Aux pin status register
Same
WBase+0x2a INT polarity control register
Same
WBase+0xc0 Read 8-bit data from D/I port Write 8-bit data to D/O port
WBase+0xc4 Reserved
Select the active I/O port
WBase+0xc8 Reserved
I/O Port 0-5 direction control
WBase+0xcc Reserved
I/O Port 6-11 direction control
WBase+0xd0 Reserved
I/O Port 12-17 direction control
Note. Refer to Sec. 3.1 for more information about wBase.
3.3.1 RESET\ Control Register
(Read/Write): wBase+0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reserved Reserved Reserved Reserved Reserved Reserved Reserved RESET\
Note. Refer to Sec. 3.1 for more information about wBase.
When the PC is first power-on, the RESET\ signal is in Low-state. This will disable
all D/I/O operations. The user has to set the RESET\ signal to High-state before any
D/I/O command.
outp(wBase,1);
/* RESET\=High
!
all D/I/O are enable now */
outp(wBase,0);
/* RESET\=Low
!
all D/I/O are disable now */
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