Omega OME-PIO-D144 - Manual (Page 33)

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) ----- 31