Memory allocations, Avoiding irq assignment conflicts – Dell Latitude L400 User Manual

Page 35

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Avoiding IRQ 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

Table 2

to configure the device for one of the available IRQ lines.

Table 2. IRQ Line Assignments

Memory Allocations

Table 3

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.

it may be faulty. A key on the built-in
keyboard may have been pressed
while the computer was booting.

be corrected,

call Dell

for technical assistance.

0250:System battery
is dead—Replace and
run Setup

The system battery does not have
enough charge to power the
computer.

Connect the computer to electrical power to recharge the battery, or
replace the battery. Then check your

system setup program

settings.

02D0:System cache
error—cache disabled

The primary cache internal to the
microprocessor has failed.

Call Dell

for technical assistance.

0251:System CMOS
checksum bad—default
configuration used

The BIOS has been changed.

CMOS has been corrupted or
modified, possibly by an application
program that changes data stored in
CMOS.

Reboot the computer. As soon as you see the Dell logo screen, press
<F2> to enter the

system setup program

and reconfigure the system. If

the problem persists,

call Dell

for technical assistance.

0230:System RAM
failed at offset:
nnnn

System RAM failed at address nnnn
in the 64-KB block at which the error
was detected.

Call Dell

for technical assistance.

0260:System timer
error

A chip on the system board may be
malfunctioning.

Run the System Set test group and the Keyboard Controller Test in
the

Dell Diagnostics

.

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® 98 and Windows Me 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.

Windows 2000 handles IRQ assignments automatically. Refer to your Windows 2000 documentation for more information.

IRQ
Line

Assigned Device

IRQ0

Reserved; generated by the system timer

IRQ1

Reserved, generated by the keyboard controller

IRQ2

Cascade from the secondary interrupt controller

IRQ3

PCI IRQC

IRQ4

Serial port; available if serial port is not configured for COM1 or COM3

IRQ5

Available

IRQ6

Generated by the diskette drive controller to indicate that the diskette drive requires the attention of the microprocessor

IRQ7

Parallel port; available if parallel port is disabled

IRQ8

Reserved; generated by the real time clock

IRQ9

PCI IRQA and SCI in ACPI mode

IRQ10

PCI IRQB, D

IRQ11

Available

IRQ12

Reserved; generated by the keyboard controller to indicate that the output buffer of the touch pad or 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 the CD-ROM or DVD-ROM drive in the external media bay to indicate that the drive requires the attention of
the microprocessor

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