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BDM-610000049 Rev G Chapter 4: Using the cpuModule 61
Hardware Interrupts
The CMX158886 cpuModule supports the standard PC interrupts listed in Table 43. Interrupts not in use by
hardware on the cpuModule itself are listed as available. Similarly, if the operating system is using APIC, more
IRQs will be available.
For external devices that require Legacy/ISA interrupts, a serial interrupt signal is available which permits access
to the CPU’s hardware interrupts. One pair of Legacy/ISA DMA request/grant signals are also available. For more
information on the serial interrupt signal, and the DMA request/grand pair, refer to Bridge Link (CN4) in
Chapter 3, Connecting the cpuModule
Note If you add any expansion modules or other peripherals to the system, you must ensure they do not
use interrupts needed by the cpuModule, or malfunctions will occur.
Table 43 Hardware Interrupts Used on the CMX158886 cpuModule
Interrupt Normal Use
0Timer 0
1Keyboard
2 Cascade of IRQ 8–15
3COM2
4COM1
5 Available
6Floppy
7Printer
8Real Time Clock
9 Available, routed to IRQ 2
10 Available
11 Available
12 Bus Mouse
14
1
1. IRQs 14 and 15 may be available if the IDE controller is
configured in Native Mode (refer to IDE Controller
Configuration—page 67)
Primary IDE hard disk
15
1
ATA/IDE Disk Chip socket
Note The cpuModule has onboard PCI devices that will claim IRQ lines. In some instances, a PCI device
will claim an IRQ line that is required by a legacy device. To reserve an IRQ for a legacy device, refer to the
PnP/PCI Configuration Setup fields in the BIOS.
Note A device’s hardware interrupt will be available for use if the given device is not present in the system
and the device is disabled in Setup.