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BDM-610000088 Rev A Chapter 4: Using the cpuModule 61
Port 1 Data register is a read/write byte direction
Interrupts
In order to use an interrupt with aDIO, the interrupt must first be selected in the BIOS setup utility under
Advanced, RTD Advanced Options, RTD aDIO, aDIO Interrupt . The Digital I/O can use interrupts 3,
5, 6, 10, and 11. To configure the aDIO interrupt, navigate to the BIOS Setup option, the “Advanced”, “RTD
aDIO”, and “aDIO Interrupt” menu options. The BIOS will automatically reserve the selected interrupt so
that is it not assigned to PCI devices. Then, select the appropriate interrupt mode in the DIO Control register.
Advanced Digital Interrupts
There are three Advanced Digital Interrupt modes available. These three modes are Event, Match, and
Strobe. The use of these three modes is to monitor state changes at the aDIO connector. Interrupts are
enabled by writing to the Digital IRQ Mode field in the DIO-Control register.
Event Mode
When this mode is enabled, Port 0 is latched into the DIO-Compare register. The aDIO circuitry includes
deglitching logic. To enter Event mode, set bits [4:3] of the DIO-Control register to “10”.
Match Mode
When this mode is enabled, Port 0 is latched into the DIO-Compare register. The aDIO circuitry includes
deglitching logic. To enter Match mode, set bits [4:3] of the DIO-Control register to “11”.
Note Make sure bits [4:3] are set BEFORE writing the DIO-Compare register. If you do not
set them first, the contents of the DIO-Compare register could be lost because the Event mode
latches in Port 0 into the DIO-Compare register.