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7.794 bytes |
Service Hints & Tips |
Document ID: LWIK-3VCNT3 |
TP 600,770 - Sharing IRQs between the DSP controller and the modem
Applicable to: World-Wide
The ThinkPad Modem function is supported by a digital signal processor (DSP) called IBM Advanced Communications Processor. The ThinkPad Modem usually uses two IRQs to handle the DSP interrupt and the modem interrupt. However, by sharing an IRQ between these two devices, you can free one IRQ so that you can use it for another device. If a new device is installed in the system that uses an IRQ, and there are none in the system to give, Windows 9x should automatically choose (through PnP) the proper configuration for the ACP Modem so that the IRQs are shared between the DSP and the Modem. A user can also manually adjust the ThinkPad Modem properties to force Windows 9x to share the IRQs.
Note
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o Do not have your computer set in an IRQ-shared status when installing the ThinkPad Modem. If your computer is already in a sharing status, disable the status before you start the installation. o An IRQ can be shared only in Windows 9x. You must disable the status before you start rebooting another operating system. |
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An IRQ can be shared only in Windows 9x. If you have a multi-partitioned hard disk drive or have multiple hard disk drives, and reboot another operating system or install another operating system, the CMOS status and the hardware settings might not remain consistent and the devices sharing an IRQ might become unusable. It is recommended that you use the system in its default IRQ status, unless you must have the IRQ shared-- because you are using multiple PC Cards and the docking station simultaneously. |
To manually share an IRQ, do the following:
1.) Click on Start, Programs, ThinkPad and ThinkPad Configuration.
2.) Click on the Internal Modem icon.
3.) Click on the Device Manager button.
4.) Double-click on IBM Digital Signal Processor.
5.) Double-click on ThinkPad Digital Signal Processor.
6.) Add a check mark in the Disable in this hardware profile check box by clicking on it; then click on OK.
7.) Double-click on ThinkPad Digital Signal Processor.
8.) Click on the Resources tab.
9.) Click on Set Configuration Manually.
10.) Remove the check mark from the Automatic Settings check box by clicking on it.
11.) Select Basic Configuration 0005.
Make sure that the list is as follows:
I/O 130-13F
I/O 2F8-2FF
IRQ 3
DMA 7
Note
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If Basic Configuration 0005 is not available then open a Dos window and enter: Make sure that DMA is 7. If it is not 7, double click on Direct Memory Access and specify 07 for Value; then click on OK. |
12.) Click on the General tab.
13.) Remove the check mark in the Disable in this hardware profile check box by clicking on it; then click on OK.
14.) Restart your computer.
To disable sharing an IRQ, do the following:
1.) Click on Start, Programs, ThinkPad and ThinkPad Configuration.
2.) Click on the Internal Modem icon.
3.) Click on the Device Manager button
4.) Double-click on IBM Digital Signal Processor.
5.) Double-click on ThinkPad Digital Signal Processor.
6.) Click on the Resources tab.
7.) Click on the Automatic Settings and remove the check mark.
8.) Select Basic Configuration 0001.
9.) Scroll the Resource Settings list box. Locate and double-click on the second IRQ 3 resource in the Resource Type column.
10.) Specify 10 for Value and click on OK.
11.) Make sure that there are no conflicting devices indicated in the Conflicting Device list.
ADDITIONAL INFORMATION:
What is the downside of IRQ sharing? It is possible that you will have performance problems running the Intel Video Phone application. This application stresses the entire system, and by sharing IRQs, the system can run into resource problems. If you have another operating system installed on your machine through Dual Boot, Boot Manager, Windows NT startup screen, etc... you will have problems using the modem because these other operating systems do not support IRQ sharing. If you share the IRQs in Windows 9x, and then format the hard drive and installs another operating system, you will need to unshare the IRQs in order to use the modem. To do this, follow the procedure outlined above.
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Hint Category |
Communications, Windows 95, Windows 98 | |
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Date Created |
11-06-98 | |
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Last Updated |
28-01-99 | |
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Revision Date |
28-01-2000 | |
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Brand |
IBM ThinkPad | |
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Product Family |
ThinkPad 600, ThinkPad 600E, ThinkPad 770, ThinkPad 770E/ED, ThinkPad 770X, ThinkPad 770Z | |
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Machine Type |
2645, 2646, 9549, 9544, 9545 | |
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Model |
Various | |
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