Specifications

HARDWARE INSTALLATION
2-14 PP 41x/03x
2.9.1 PMC Site 2 Bus Speed and Mode Selection
The PCI bus connecting to PMC Site 2 can operate at various bus speeds and modes, namely, 33
MHz PCI, 66 MHz PCI, 66 MHz PCI-X and 100 MHz PCI-X. The bus speed and mode is
determined by the settings of two option switches. These switches are shown in Figure 2-13.
Switch 1 should normally be in the ON position. This forces the bus to operate in PCI mode. If a
PCI-X capable PMC module is fitted, Switch 1 should be set to the OFF position. This will allow the
bus to operate in PCI-X mode.
Switch 4 sets the speed range of the bus. If Switch 4 is OFF this will be an even multiple of 25
MHz. If Switch 4 is ON this will be an even multiple of 33 MHz.
Switch 4 should normally be in the ON position. If a 100 MHz PCI-X PMC module is fitted, Switch 4
should be set to the OFF position.
WARNING: The PP 41x/03x cannot automatically determine the speed capability of a
PCI-X capable PMC module. Switch 4 must be set correctly. If you are unsure of the
speed capability of your PMC module, set Switch 4 to the ON position.
WARNING: Do not operate the PP 41x/03x board with Switch 1 OFF, Switch 4 ON and
no PMC module fitted.
Figure 2-13 PMC 2 PCI Bus Speed Select and PCI-X Enable Switches