Teledyne Princeton Instruments PI-MTE, System Manual

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82 PI-MTE System Manual Issue 6
7.10 Error Occurs at Computer Power Up
If an error occurs at boot up, either the Interface is not installed properly or there is an
address or interrupt conflict. Turn off the computer, try a new address or interrupt and
reinstall the card. Be sure the Interface card is firmly mounted in the slot.
NOTE:
Since interrupts and DMA channels cannot be shared, make
sure no other boards in your computer use this interrupt or
these DMA channels.
7.10.1 Conflicts
One of the many advantages that PCI offers over ISA is that the whole issue of address
and interrupt assignments is user transparent and under BIOS control. As a result, users
typically do not have to be concerned about jumpers or switches when installing a PCI
card. Nothing more should be required than to plug in the card, make the connections,
and operate the system. As it turns out, however, in certain situations conflicts may
nevertheless occur and user intervention will be required to resolve them.
Typical PCI motherboards have both ISA and PCI slots and will have both PCI and ISA
cards installed. In the case of the ISA cards, the I/O address and Interrupt assignments
will have been made by you and the BIOS will not know which addresses and interrupts
have been user assigned. When a PCI card is installed, the BIOS checks for available
addresses and interrupt levels and automatically assigns them so that there are no PCI
address or interrupt conflicts. However, because the BIOS doesn't know about the
user-assigned ISA I/O address and interrupt level assignments, it is possible that a PCI
card will be assigned an address or interrupt that is already assigned to an ISA card. If
this happens, improper operation will result. Specifically, the problems could range
from erratic operation under specific conditions to complete system failure. If such a
conflict occurs, because you have no control over the PCI address and interrupt
assignments, there will be no recourse but to examine the ISA assignments and change
them to values which do not conflict. Most (but by no means all) ISA cards make
provision for selecting alternative I/O addresses and interrupt levels so that conflicts
can be resolved. Software is available to help identify specific conflicts.
The following example may serve to illustrate the problem. Suppose you had a system
with an ISA network card, a PCI video card and an ISA sound card. Further, suppose that
you were then going to install a PCI Serial Buffer card. Before installing the PCI Serial
card, the I/O address and interrupt assignments for the installed cards may be as shown
in
Table 7-3 .
Table 7-3: I/O Address & Interrupt Assignments before Installing Serial Card
Slot Type Status I/O Address Interrupt
1 (ISA) ISA Network Card 200-210 11
2 (PCI) PCI Video Card FF00-FFFF 15
3 (ISA) ISA Sound Card 300-304 9
4 (PCI) Empty N/A N/A