Backplane Architecture
30
Model 6476 User Guide
3 • System Architecture
A system CPU uses J1 and J2, but 32-bit peripherals cards only need to use J1 for full CompactPCI function-
ality. J3 through J5 on 4U cards can be user-defined I/O. Optional buses, such as the CT H.110 bus, use the
J4 position.
J1/P1 & J2/P2 connectors
The CompactPCI bus spans the J1/P1 & J2/P2 connectors, with 32-bit PCI implemented on J1/P1 and full
64-bit PCI implemented on J2/P2 on the Model 6476 Midplane. J1/P1 is always devoted to 32-bit PCI in
CompactPCI systems, however, use of J2/P2 for 64-bit PCI can be optional. For instance, in a 3U system, J2/
P2 may be defined for user I/O, or sub-buses like the CT H.110 bus. J2 is always used on system slot boards to
provide arbitration and clock signals for peripheral boards.
J3/P3 through J5/P5 connector
J3/P3 through J5/P5 connectors, available only in 4U systems, are generally defined for user I/O. However,
sub-bus interconnects (for example, CT H.110 bus) can be configured on the J4/P4 connector.
Reserved Pins
There are bused and non-bused reserved pins as noted below:
•
The BRSVPxxx signals SHALL be bused between connectors and are reserved for future CompactPCI def-
inition.
•
The RSV signals are non-bused signals that SHALL be reserved for future CompactPCI definition.
Power Pins
The 4U Model 6476 Backplane/Midplane has a customer-selectable signaling environment. All connectors on
the 4U Model 6476 Backplane/Midplane provide pins for +5V, +3.3V, +12V and -12V operating power. In
addition, there are power pins lV(I/O). The V(I/O) power pins on the connector are used to power the
buffers on the peripheral boards, allowing a card to be designed to work in either interface. CompactPCI sup-
ports this dual-interface scheme by utilizing backplane connector keying.
Backplane Architecture
Patton Electronics Company, 4U Model 6476 Backplane/Midplane provides eight 6U board locations with
20.32 mm (0.8 inch) board center-to-center spacing. The 6U cards are stacked horizontally in the 4U model,
however, the special design provides vertical convection cooling with the installed 6470-FT plug-in fan tray
module.
There are also eight 3U x 160mm slots on the front right side, called the “Power Bay”, to mount Patton Power
Supply Modules configured for external DC or AC power input, or other cPCI compatible power modules.
A rear view of the 4U Model 6476 is shown in
figure 12
.
