B-2 APPENDIX B: SPECIFICATIONSConfiguration OptionsThis section describes the configuration options for the3C689 adapter. The following options are available:n Ring Speedn I/O Base Addressn MMIO Address Locationn Shared RAM Page Size and Address Rangen Interrupt Request LevelThese options are described on the following pages.Ring SpeedThe 3C689 adapter operates at either 4 or 16 Mbps ringspeed and must match the speed of the token ring network.The default is 16 Mbps.I/O Base AddressThe I/O base addresses allowed are Primary or Secondary.The Primary default address is A20h. If a system resourceconflict continues, you may have to change the settings ofother adapters or options that are in your computer.MMIO Address LocationThere are 16 possible 8 KB blocks of PC memory that can beassigned for accessing the MMIO address area of the 3C689adapter. The factory default MMIO address is CC000. The 16MMIO address locations are listed below, with the defaults inbold.C0000–C1FFF D0000–D1FFFC2000–C3FFF D2000–D3FFFC4000–C5FFF D4000–D5FFFC6000–C7FFF D6000–D7FFFC8000–C9FFF D8000–D9FFFCA000–CBFFF DA000–DBFFFCC000–CDFFF DC000–DDFFFCE000–CFFFF DE000–DFFFF
