WinSystems PCM-VDX-2-512, Product Manual

Page: 35 / 75

140808 PRODUCT MANUAL PCM-VDX-2-512 35
Setup GPIO Registers
Port 0 Port 1 Description
Data Register 78H 79H
Direction Register 98H 99H
0: GPIO pin is input mode
1: GPIO pin is output mode
If send value 0FH to port 98H, it means that GPIO port 0 [7-4] are input mode and port[3-0] are output mode.
If send value 00H to port 98H, it means that GPIO port 0 [7-0] are input mode.
If send value FFH to port 98H, it means that GPIO port 0 [7-0] are output mode.
If send value 03H to port 98H, it means that GPIO port 0 [7-2] are input mode and port[1-0] are output mode.
GPIO with Interrupt
The Vortex86DX GPIO ports 0 and 1 support interrupt trigger. To save CPU performance, interrupt can be used instead
of polling GPIO. GPIO port 0 interrupt registers are at offset DCh~DFh south bridge and GPIO1 registers are at offset
E0h~E3h.
Steps to setup GPIO to trigger interrupt:
1. Configure interrupt mask register to determine which GPI can trigger interrupt individually.
2. Set trigger level (high or low) for each GPI.
3. Set period time that interrupt will be generated while the event loading time of any one of GPI[7-0] is longer than the
time parameters.
4. Select IRQ.
5. Set interrupt trigger once or continuously.
For more information on programming GPIO, see Software Drivers & Examples section on our website.