Hardware interrupts – IBM CMX58886CX User Manual
Page 63
BDM-610000050
Rev A
Chapter 4: Using the cpuModule
55
Hardware Interrupts
The CMX58886CX cpuModule supports the standard PC interrupts listed in Table 38. 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
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 38
Hardware Interrupts Used on the CMX58886CX cpuModule
Interrupt
Normal Use
0
Timer 0
1
Keyboard
2
Cascade of IRQ 8–15
3
COM2
4
COM1
5
Available
6
1
1. Floppy disk interrupt, INT6, is available for use if no floppy
disk is present in the system and floppy disk is disabled in
Setup.
Floppy
7
Printer
8
Real Time Clock
9
Available, routed to IRQ 2
10
Available
11
Available
12
Bus Mouse
14
2
2. Hard disk interrupt, INT14, is available for use if no hard disk
drive is present in the system and hard disk is disabled in
Setup.
Primary IDE hard disk
3
3. IRQs 14 and 15 may be available if the IDE controller is
configured in Native Mode (refer to
15
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.