Installing Pmcs; Pmc Site (Vio); Figure 1-4 Keypin Installation And Setup - ABACO VMICPCI-7055 Hardware Reference Manual

1.7 Installing PMCs

Publication No. 500-657055-000 Rev. G

1.7.1 PMC Site (VIO)

VIO is the I/O voltage used for PCI bus termination. The PCI bus interface
requires strong parallel (pull-up) termination. Initially, the voltage for the pull-
ups was +5 V. Over time, with the need for power reduction and higher speeds,
+3.3 V devices became prevalent. +3.3 V devices can easily drive TTL signaling.
Higher speed PCI buses utilize +3 V termination.

Figure 1-4 Keypin Installation and Setup

CAUTION
When Installing the keypins on the two PMC sites, the two keypins MUST be setup for the same voltage
level (Either in the 5 V position (installed) or in the 3.3 V (removed) position). This is due to the keypins
being on the same bus, if installed incorrectly this could cause damage.
Keypins (KP5 and KP6)
KP5
Installed = 5.0V
(Factory Default)
Field removable
for 3.3V
KP6
Installed = 5.0V
(Factory Default)
Field removable
for 3.3V
J5
J3
J2
J1
Handling and Installation 25