Omega OME-PIO-D144 - Manual (Page 8)

2.2 I/O Port Location
There are eighteen 8-bit I/O ports in the OME-PIO-D144. Every I/O port can be
programmed as D/I or D/O port. When the PC is first powered up, all eighteen ports
are used as D/I ports. The I/O port location is given as following:
Connector of OME-PIO-D144 PA0 to PA7
PB0 to PB7 PC0 to PC7
CN1 CN1_PA CN1_PB CN1_PC
CN2 CN2_PA CN2_PB CN2_PC
CN3 CN3_PA CN3_PB CN3_PC
CN4 CN4_PA CN4_PB CN4_PC
CN5 CN5_PA CN5_PB CN5_PC
CN6 CN6_PA CN6_PB CN6_PC
Refer to Sec. 2.1 for board layout & I/O port location.
Note: PC0, PC1, PC2, PC3 of CN1 can be used as interrupt signal source. Refer
to Sec. 2.5 for more information.
2.3 Enable I/O Operation
When the PC is first powered up, all operation of D/I/O port are disable. The
enable/disable of D/I/O is controlled by the RESET\ signal. Refer to Sec. 3.3.1 for
more information about RESET\ signal. The power-on states are given as following:
• All D/I/O operations are disable
• All eighteen D/I/O ports are configured as D/I port
• All D/O latch register are undefined.(refer to Sec. 2.4)
The user has to perform some initialization before using these D/I/Os. The
recommended steps are given as following:
Step 1: Make sure which ports are D/O ports.
Step 2: Enable all D/I/O operation.(refer to Sec. 3.3.1).
Step 3: Select the active port (refer to Sec. 3.3.8).
Step 4: Send initial-value to the D/O latch register of this active port.
(Refer to Sec. 2.4 & Sec. 3.3.7)
Step 5: Repeat Step3 & Step4 for all D/O ports
Step 6: Configure all eighteen D/I/O ports to their expected D/I or D/O state.
(Refer to Sec. 3.3.9)
Refer to DEMO1.C for demo program.
OME-PIO-D144 User’s Manual (Ver.2.1, Sep/2001) ---- 6