User guide

8.3 PCI I/O Companion Card

You can connect an optional PMC I/O companion card to the I/O module. This

card contains a 21052 PCI-to-PCI bridge chip and two sets of PCI mezzanine card

(PMC) connectors that allow you to add one double-width or two single-width PCI

PMC modules. One of the PMC connector sets includes a third connector that

allows I/O access through the P2 connector.

PCI bus arbitration supports two PCI devices with up to four interrupt request

lines each. The PCI clock is driven from the Digital Alpha VME 4 assembly

at a frequency of 32 MHz. The card connectors provide 3 V and 5 V supply

voltages. Although you can have mixed supply voltages between cards, the PCI

bus signaling voltage must be 5 V. The voltage selector jumper is located on the

PMC I/O companion card and must be conﬁgured by the installer.

PCI bus 8–11