Memory allocations, Avoiding interrupt assignment conflicts – Dell Latitude CPx H User Manual
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4-4-1
Serial port failure.
Run the Serial/Infrared Ports tests in the
5-1-2
No usable memory.
Run the System Memory tests in the
Avoiding Interrupt Assignment Conflicts
Problems can arise if two devices attempt to use the same interrupt request (IRQ) line. To avoid this type of conflict, check the
documentation for the default IRQ line setting for each installed device. Then consult
to configure the device for one of the
available IRQ lines.
NOTES: Installed devices cannot share the same COM port address. The default address of your computer's serial port is
COM1.
To view IRQ line assignments in the Microsoft® Windows® 95 and Windows 98 operating systems, click the Start button,
point to Settings, and click Control Panel. Double-click the System icon. Select the Device Manager tab, and then double-
click Computer.
Table 3. IRQ Line Assignments
IRQ
Line
Reserved/Available
IRQ0
Reserved; generated by the system timer
IRQ1
Reserved; generated by the keyboard controller to signal that the keyboard output buffer is full
IRQ2
Reserved; generated internally by the interrupt controller to enable IRQ8 through IRQ15
IRQ3
Available for use by a PC Card unless the integrated serial port or infrared port is configured for COM2 or COM4
IRQ4
Available for use by a PC Card unless the integrated serial port or infrared port is configured for COM1 (the default) or
COM3
IRQ5
Available for use by the audio controller
IRQ6
Generated by the diskette drive controller to indicate that the diskette drive requires the attention of the microprocessor
IRQ7
Available for use by a PC Card or audio controller if the parallel port is disabled
IRQ8
Reserved; generated by the system I/O controller's RTC
IRQ9
Reserved; generated by the video controller
IRQ10 Available for use by a PC Card or audio controller unless the C/Port Family APR or C/Dock Family Expansion Station is
attached
IRQ11 Generated by USB, PC Card, and audio controllers; available for use by a PC Card
IRQ12 Reserved; generated by the keyboard controller to indicate that the output buffer of the DualPoint integrated pointing
device or the external PS/2 mouse is full
IRQ13 Reserved; generated by the math coprocessor
IRQ14 Reserved; generated by the hard-disk drive to indicate that the drive requires the attention of the microprocessor
IRQ15 Reserved; generated by CD-ROM drive in the modular bay to indicate that the drive requires the attention of the
microprocessor
Memory Allocations
provides a map of the conventional memory area. When the microprocessor or a program addresses a location within the
conventional memory range, it is physically addressing a location in main memory.