60
CMA34CR cpuModule
BDM-610000083
Rev L
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, I/O Devices, aDIO Configuration, 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 at 8.33 MHz. The aDIO circuitry
includes deglitching logic. The deglitching requires pulses on Port 0 to be at least 120 ns in width. As long as
changes are present longer than that, the event is guaranteed to register. Pulses as small as 60 ns can register as
an event, but they must occur between the rising and falling edge of the 8.33 MHz clock. 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 at 8.33 MHz. The aDIO circuitry
includes deglitching logic. The deglitching requires pulses on Port 0 to be at least 120 ns in width. As long as
changes are present longer than that, the match is guaranteed to register. Pulses as small as 60 ns can register as
a match, but they must occur between the rising and falling edge of the 8.33 MHz clock. 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.
Summary of Contents for cpuModules CMA34CR
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