Measurement Computing STLITE-PCI-8x - Manual (Page 10)

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4 POWERING-UP/DOWN
4.1 SEQUENCE FOR APPLYING POWER
It is important that higher-numbered PCI buses in your system’s hierarchy be powered-up and at a stable state at
the time the host computer comes up and issues a master power-on bus reset. In systems that perform automatic
PCI bus configuration, this allows the configuration software to recognize the PCI bus hierarchy and all attached
devices.
NOTE: It is desirable for the host computer and the PCI Expansion Chassis to receive their AC power from the
same, protected, local AC power source.
1. POWER-ON – Place the AC power switch on the rear panel of the PCI Expansion Chassis to the on ( I )
position.
2. Apply power to the host system.
NOTE: If you have multiple (daisy-chained) PCI Expansion Chassis, apply power to the most “downstream”
unit first, then the next ‘upstream” unit, etc., and finally, power-up the host computer. (See section 5.)
4.2 POWERING DOWN
There is no requirement for sequential powering-down of the system. You can shut down system units in any
order you wish.
5 MULTIPLE CHASSIS INSTALLATION
5.1 INTRODUCTION
The PCI bus is a hierarchical bus where PCI-to-PCI Bridges can be used to add “levels” to the PCI bus
hierarchy. The bus is defined by the PCI Local Bus Specification standard.
Thus, you can add two or more STLITE-PCI-8T chassis to your system. You are free to select either a “daisy-
chain” (serial) manner or a fan-out (serial/parallel) fashion. Each configuration has its own advantages and
applications.
In a daisy chain configuration (Figure 5-1), expansion chassis are added serially at the end of the PCI bus
hierarchy, one bridge after another. This adds to the local PCI bus by increasing the number of active local bus
levels in the system configuration.
Each PCI bridge has a primary side and a secondary side. Take, for example, the addition of a bridge to existing
PCI Bus 0. The new bridge is attached to the secondary side of the first bridge and the new bridges secondary
side becomes Local Bus 1. The primary side is defined as the side attached to the lower numbered, or upstream
PCI Local Bus. A bridge attached to the secondary side of the new bridge (Bus 1) would be assigned a higher
number (Bus 2) and considered downstream of Bus 1.
Note: When expanding from an existing chassis in either daisy-chain or fan-out mode the STLITE-PCI-
HOST card(s) must be installed in Slots 5-11. Please do not install the STLITE-PCI-HOST in Slot 4.
5.2 DAISY-CHAIN CONFIGURATION
The PCI bus in your host computer is typically numbered “0”. Each addition of a bridge adds a new bus level
into the hierarchy. The Host PCI Bridge card, when plugged into the host computer, has as its primary side, Bus
0. Its downstream side is Bus 1 (Figure 5-1).