Read/write 8-bit data register, Active i/o port control register, 7 read/write 8-bit data register – Omega OME-PIO-D144 User Manual
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3.3.7 Read/Write 8-bit data Register
(Read/Write): wBase+0xc0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
D7 D6 D5 D4 D3 D2 D1 D0
Note. Refer to Sec. 3.1 for more information about wBase.
There are eighteen 8-bit I/O port in the OME-PIO-D144. Every I/O port can be
programmed as D/I or D/O port. Refer to Sec. 3.3.9 for D/I or D/O selection. When
the PC is first power-on, all eighteen ports are used as D/I port.
outp(wBase+0xc0,Val);
/* write to D/O port */
Val=inp(wBase+0xc0);
/* read from D/I port */
3.3.8 Active I/O Port Control Register
(Read/Write): wBase+0xc4
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
D7 D6 D5 D4 D3 D2 D1 D0
Note. Refer to Sec. 3.1 for more information about wBase.
There are eighteen 8-bit I/O port in the OME-PIO-D144. Only one I/O port can be
active at the same time.
outp(wBase+0xc4,0);
/* I/O port_0 is active now */
outp(wBase+0xc4,1);
/* I/O port_1 is active now */
outp(wBase+0xc4,17);
/* I/O port_17 is active now */
Refer to Sec. 2.2 for I/O port location.
OME-PIO-D144 User’s Manual (Ver.2.1, Sep/2001)
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