AST RESEARCH, INC. INFORMATIONAL BULLETIN # 0014 09/24/96 TITLE: Configuration Tips: PCI, Manhattan S SUMMARY This bulletin has been prepared to assist customers with the selection and installation of PCI devices in their Manhattan S/6200 and Commerce Pro servers. Most of the information is generally applicable to PCI devices and is not specific to any version of PCI specifications. Some information is specific to the Manhattan S/6200 and Commerce Pro servers. In these cases, the difference will be noted. This bulletin provides information related to the following systems: 501832 and 503076. NOTES BACKGROUND The Manhattan S/6200 and Commerce Pro servers are designed to comply with the industry standard PCI bus. This bulletin provides installation tips that will assist with selecting and installing PCI adapters and help to avoid configuration issues. Generally, configuration issues with PCI devices are caused by one or more of the following problems: 1. PCI Adapters which do not completely support the PCI specification. 2. Differences between interpretations of the PCI specification by device designers. 3. Additional features and enhancements added by device manufacturers, which do not properly interact with other standard PCI devices. 4. Mixing PCI and ISA adapters in the same system. 5. Limitations within the PCI specification as to the number of IRQ lines available to PCI devices. Following the checklist and guidelines below will minimize the above factors and resolve the largest share of PCI configuration issues. MANHATTAN S/6200 AND COMMERCE PRO REQUIREMENTS The Manhattan S/6200 and Commerce Pro servers are designed for use with three types of adapter boards: 1. 32-bit, 5 volt PCI adapters 2. 32-bit EISA adapters, and 3. 16-bit ISA adapters. The PCI bus is comprised of the top six adapter slots in the system. There are two PCI busses in the system, connected together by a PCI Bridge controller chip. The top two PCI slots are located on the Primary PCI bus, which is sometimes referred to as "ahead" of the PCI bridge. The next four PCI slots are located on the Secondary PCI bus, which is sometimes referred to as "behind" the PCI bridge. Keep the slot location in mind when installing PCI devices, because some adapter device drivers do not support PCI Bridges. If an adapter is not working correctly when installed on the Secondary PCI bus, try to install the adapter on the Primary PCI bus. If the adapter works properly on the Primary PCI bus, contact the manufacturer of the adapter and obtain a driver that supports PCI Bridges. Also consider that some of the PCI slots share PCI Interrupt Request Lines (PCI IRQs) with other PCI slots in the system. The PCI specifications allow system manufacturers to share PCI IRQs with multiple PCI slots. However, some adapters do not operate properly when they are forced to share an IRQ with another device. Typically, obtaining a later device driver from the manufacturer will resolve these problems, because most adapter designers now ensure that their drivers support these configurations. The table below lists the slots which share PCI IRQs in the Manhattan S/6200 and Commerce Pro servers. If a PCI device is not working correctly, try to install it in a slot that does not share its PCI IRQ. Pre-Assigned IRQ Settings in Manhattan S/6200 and Commerce Pro Slot Number Shares IRQ with Slot Number 1 5 2 6 3 Not shared 4 Not shared 5 1 6 2 PCI adapters may be available in 5 volt, 3.3 volt, and universal (supports both the 5 volt and 3.3 volts) variations. Both 5 volt and universal adapters can be physically installed in the Manhattan S/6200 and Commerce Pro servers. A 3 volt adapter can not be installed. Ensure that all PCI adapters are either 5 volt or universal. NOTE: At the time this bulletin was authored, no 3.3 volt or universal adapters were readily available on the market. CHECKLIST When selecting PCI adapters, always ask the following questions: 1. Does the PCI adapter operate correctly in a 32 bit, 5 volt PCI bus slot? These are the two primary specifications that should be considered when selecting a PCI adapter. A PCI adapter that will not operate in a 32-bit, 5 volt PCI slot will not function in the system. 2. Does the adapter work on both sides of a PCI - PCI bridge? As indicated above, some adapters may not work properly "behind" the PCI Bridge. If the adapter will not function behind the PCI bridge, it may only be installed in PCI slot number 1 or 2. Check with the adapter vendor to ensure that the device will operate properly in a PCI bridge environment. 3. Does the adapter support PCI IRQ sharing? If the PCI adapter does not support PCI IRQ sharing, then it may only be installed in PCI slot number 3 or 4. These slots do not share their PCI IRQ. Check with the adapter vendor to ensure that the PCI device supports sharing of PCI IRQs. As a troubleshooting and performance aid, it is best to share PCI IRQs of the same device type and manufacturer. The designer of the device, when writing a driver that shares IRQs, will have the most knowledge about the manner is which their own devices behave in a shared environment. AST also suggests that identical adapters be used in a shared PCI IRQ environment. A driver could operate incorrectly if two adapters are similar, but not identical. CONSIDERATIONS FOR EISA DEVICES There are three slots provided in the system for EISA bus adapters. These adapters are configured through the AST System Configuration Utility. When installing an EISA adapter into the system, always configure the EISA adapter prior to installing PCI adapters. EISA adapters use "static" resources, meaning that once configured through the AST System Configuration Utility, they will not change without re-running the utility. The EISA adapter's resources will then be "sensed" by PCI devices. The PCI device will then attempt to avoid conflicts with the EISA adapter. As a general rule, PCI devices should not be configured to share resources with EISA devices. While there may be cases when such a configuration is possible, AST does not suggest to configure the system in this manner. CONSIDERATIONS FOR ISA LEGACY DEVICES An ISA Legacy device is a 16-bit ISA adapter, which is not Plug-and-Play (PnP) capable. This type of device is not aware of other devices in the system and can not be reconfigured by the AST System Configuration Utility. Typically, an ISA Legacy adapter will be configured through switches or jumpers on the adapter board, or through a special configuration utility from the device manufacturer. Legacy ISA adapters are the most troublesome technology to mix in a system with EISA and PCI devices, because of the inflexibility of the ISA adapter and the inability of EISA and PCI devices to "sense" the existence of ISA legacy adapters. In order to avoid conflicts, you must know the resources used by the ISA adapter. If you do not know which system resources an ISA adapter uses, contact the manufacturer of the adapter before installing the adapter in the system. Once you have established the resources that will be used, install the ISA Legacy adapter in the system prior to installing any EISA or PCI devices. Run the AST System Configuration Utility and manually add the ISA adapter to the system and lock its resources. This can be accomplished by either creating a new .CFG file in the AST System Configuration Utility, or by adding a .CFG file from the manufacturer if one is available. NOTE: It is important to understand that by adding information to the AST System Configuration Utility about ISA Legacy adapters, EISA and PCI adapters will become "aware" of the existence of the ISA adapter in the system. However, changing the information in the utility program will not change the actual configuration of the ISA Legacy adapter. Additionally, if the information supplied to the utility is incorrect, the EISA and PCI devices will be "aware" of the wrong information. After adding the ISA adapter information to the AST System Configuration Utility, add EISA adapters and run the AST System Utility again. Finally, install the PCI devices. Adding devices in this order will ensure the orderly assignment of resources to the PCI devices in the system. CONSIDERATIONS FOR PLUG-AND-PLAY ISA DEVICES Plug-and-Play (PnP) ISA devices are similar to ISA Legacy devices, with the addition of "dynamic" resource configuration. Resources for these devices are typically configured every time the adapter senses a change in the system's resource. Typically, the number of system resources variations is limited to a pre-selected group. If an ISA board is operating as a PnP device, it will configure itself to avoid conflicts with other devices in the systems. However, if the PnP features of the ISA device are disabled, the device will operate as a standard ISA legacy device and will exhibit any of the problems noted above concerning ISA legacy products. Generally, ISA PnP resources can be locked by a utility supplied by the manufacturer. Contact the device manufacturer to obtain any utilities that can be used to lock resources and prevent dynamic reconfiguration. After the ISA PnP configuration has been locked into place, follow the suggestions above, treating the ISA PnP device as if it were an ISA Legacy device. TAN N/A --------------------------------------------------------------------- The information in this data sheet is subject to change without notice. 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