Pci2 Irq Assignments

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Lotus100

Let me reference the 3 charts in the manual for the Asus manual for the P8Z68-V_PRO_GEN3.
*There's the Slot Description Chart (SDC) at section 2-12, page 30.
*There's the VGA Configuration Chart (VGAC) at section 2-12, page 30 (same page).
*There's the PCIEX16_3 configuration Chart (PCIEX16) at section 2-13, page 31.
*There's the IRQ assignments for this motherboard (IRQ) at section 2-13, page 31.

Please note: I will use my abbreviations in () above to try to make things easier for us.

The following will be closed ended questions to make you job of answering my questions easier. Please just answer what I am asking directly. If I need to be corrected then please just explain the subject of my question better without going beyond (cause that's what can add to my confusion). Thanks.

With this in mind:

1. The PCIEX16 is a chart that focuses on just the Slot #7 in the SDC. I understand that Slot's #2 and #5 can also accept the PCIX16 card too, but this chart seems to be focused only upon Slot #7. This is why Slot #2 and Slot #5 have the "_1 and _2" added as a suffix to the PCIEX16. And why Slot #7 has the "_3" suffix. Am I correct here? Yes or No, please explain.

Okay, so let's say my first question is accurate, then:

2. The X-Axis of the PCIEX16 shows the five options of PCI cards that can go into the PCIEX16_3 or Slot #7 location. Is this correct? Yes or No, please explain.

So, let's say my second question is accurate, then:

3. The Y-Axis of the PCIEX16 shows the different configurations for Slot #7?
Is this correct? Yes or No, please explain.

4. The different configurations of the Y-Axis are chosen by the BIOS? (Note: I haven't got up to reading about this in the manual yet. But I'll get there! Free time is limited to learn about all this stuff.)
Yes or No, please explain.

5. Now, if I'm right about my reading of this PCIEX16 chart and if I am using the X4 mode, then I will be required to use Slot #7 or PCIEX16_3 for my PCIEX16 card. And, I will not be able to utilize any other PCI card (see the X-Axis of the PCIEX16 chart) at the same time, even in any other Slot 1-6. Is this correct? Yes or No, please explain.

6. If I am using the Auto Mode of the PCIEX16 chart then a PCIEX16 card in Slot #7 will only run at 1 lane? Yes or No, please explain.

7. In addition, if I am using the Auto Mode of the PCIEX16 chart and Slot #7 contains a PCIEX16 card then Slot #'s 1, 2, 4,5 and 6 are available for the other types of PCI cards? Slot #7 will use only 1 lane (question #6). The other cards can be: a PCIEX1 card, a USB3_34 card or a ESATA card.
And, any other PCI card option used will run at 1 lane each. It seems you can only use a maximum of four PCI cards on any of the three different modes. Is this correct? Yes or No, please explain.

8. If there are a total of 16 lanes which can be used then is each X1 = to 4 lanes? This means that using X1 with four different PCI cards that equals 4+4+4+4 = 16 lanes? Is this correct? Yes or No, please explain.

9. The "X#" is not a multiple of how many bytes are sent down a particular lane. It is just an indication of how many of the 16 lanes are being used?
Is this correct? Yes or No, please explain.

10. Using the X1 Mode, only Slot #'s 7, 1, and 3 can be used, even for a USB3_34 PCIE card or PCIE ESATA card. Is this correct? Yes or No, please explain. (Note: By this question I think you're getting an idea what is causing me confusion in looking upon this PCIEX16 chart.)

11. The VGAC shows that there are only two ways you can configure a PCIEX16 card(s). If you're using a Single then you must put that PCIEX16 card into Slot #2, which will use all 16 lanes. The other PCIE cards must use the other available slots. Is this correct? Yes or No, please explain.

12. The VGAC allows for a Dual configuration, which requires you to use Slot #'s 2 and 5, which will only use 8 lanes each. The other PCIE cards must use the other available slots. Is this correct? Yes or No, please explain.

I think you can understand by now how confusing this stuff can be to somebody new to building their first computer. Gosh, I sure wish the manual and tech writer would realize that not everybody is a computer engineer. Yet, basic consumers go into a computer store and are faced with computer parts that they have no idea about. And getting educated on this stuff is quite a task.

I'm giving myself an award for getting this far! If others can do this then so can I.

IRQ Settings, how to view IRQ assignments and resolve IRQ conflicts.

IRQ stands for Interrupt ReQuest and refers to special numbered channels that are used by devices to get the processors attention.

For example, when you press a key on your keyboard it sends a signal to the processor via an IRQ channel (usually IRQ1) to let it know that it needs to process some data.

IRQ conflicts can occur when new hardware is installed or reconfigured. For example, it can cause problems if you have your mouse on COM 1 (IRQ4) and a modem on COM 3 (IRQ4), below is a list of the default assignments for IRQ channels in Windows.

Default ISA IRQ Assignments

IRQ 0System Timer
IRQ 1Keyboard
IRQ 2Cascaded with IRQ 9
IRQ 3Default COM2 and COM4
IRQ 4Default COM1 and COM3
IRQ 5LPT2
IRQ 6Floppy Drive Controller
IRQ 7LPT1
IRQ 8Real Time Clock
IRQ 9SEE 2
IRQ 10Open
IRQ 11Open
IRQ 12PS/2 mouse or Open
IRQ 13Math Coprocessor
IRQ 14Primary Hard Drive controller
IRQ 15Secondary Hard Drive controller

Viewing your current IRQ assignments

  • Using a mouse
    1. Hover the mouse at the top-right of your screen.
    2. Move the mouse down and click on Search.
    3. Type Control panel into the search box.
    4. Click on the Control panel icon.
    5. Click on the Hardware and Sound icon.
    6. Under Devices and Printers click on Device manager
  • Using touchscreen
    1. Swipe to the left from the right-edge of the screen.
    2. Tap on Search.
    3. Type Control panel into the search box.
    4. Tap on the Control panel icon.
    5. Tap on the Hardware and Sound icon.
    6. Under Devices and Printers tap on Device manager

Now see our section below "Opening the list of IRQs".
  1. Click on the START button then type Control panel into the search box.
  2. Click on the Control panel icon in the results (see screenshot below).

Now see our section below "Opening the list of IRQs".
  1. Click on START, click on CONTROL PANEL.
  2. If present, click on Performance and Maintenance (category view).
  3. Click on System.
  4. Click on the Hardware tab.
  5. Click the DEVICE MANAGER button.

Now see our section below "Opening the list of IRQs".

Opening the list of IRQs

Once you have Device Manager open select VIEW from the toolbar menu and then click Resources by Type.

Double click on Interrupt Request (IRQ) as seen in fig 1.1 below:



The list that appears on your machine will vary depending on the hardware you have.

If you are experiencing problems with a newly installed/configured piece of hardware and the drivers are installed correctly, then check to see if it has its own IRQ channel.

Changing IRQ Settings

Warning: Changing system resources such as IRQ channels can result in your computer not functioning correctly. Always make a note of the settings before you change anything so you can restore them back if required.

If you do have a conflict and need to change an IRQ setting:
  1. Right click on the device in the list (see above), and then select properties.
  2. Click the Resources tab.
  3. Remove the tick from the Use automatic settings option.
  4. Select a non-conflicting configuration from the pull down box.
  5. Click OK
You may find you cannot manually change your IRQ settings (the Use automatic settings will be greyed out), this is usually related to the ACPI function used by Windows XP.

To resolve conflicts with PCI or ISA cards try manually setting them in your motherboard's BIOS, or try a different slot for the newly installed device. You will usually find that by changing the slot you will change the IRQ channel as well.

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