Lenovo ThinkPad 600E ThinkPad 600 Suppliment to the User's Guide - Page 89

Chapter 6. Resolving System Resource Conflicts This chapter describes the default system resources and how to share an IRQ between two devices. Note: This chapter is only for Windows 95. Sharing an IRQ between ThinkPad Modem Devices 83 Default IRQ Assignments 86 System Resources and IRQs 86 In most cases, your computer automatically assigns the system resources when you install a new device. For example, your computer assigns such resources as the interrupt request (IRQ) level and the input/output (I/O) ports when you install a PC Card modem. Other devices might need such system resources as direct memory access (DMA) and memory. The IRQ for each system resource can have a value of 0 to 15. That is, there are 16 values that can be assigned for IRQs. Sometimes Windows 95 does not allocate the resources correctly, because the resource might already be allocated to another device. This is called a system resource conflict, or contention. In this case, you can free one IRQ by sharing an IRQ between two devices. When doing this, you need to know about the system resources available and their IRQs. This chapter describes how to solve resource conflicts by sharing an IRQ. Sharing an IRQ between ThinkPad Modem Devices 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. Copyright IBM Corp. 1998 83