1–14
Preparing for the Installation
Section 1.6.2.1 or 1.6.2.2. Section 1.6.2.1 discusses considerations that apply
when the Alpha VME SBC is being used as system controller. Section 1.6.2.2 dis-
cusses considerations that apply when the SBC is not being used as system con-
troller.
1.6.2.1 When the Alpha VME SBC is Used as System Controller
When an Alpha VME 5/352 or 5/480 SBC is the system controller in an applica-
tion, set configuration switch 4 on the I/O module to the Closed position, as
explained in Section 2.2. You must take additional action, depending on the type
of VMEbus backplane you are using:
•
Passive backplanes
If you are using a passive backplane make sure:
–
The backplane’s bus grant jumpers for slot two are not installed
–
The J11 bus grant pass-through jumper on the Alpha VME 5/352 or 5/480
SBC CPU module is not installed
•
Backplanes that grant bus access mechanically
Some VMEbus backplanes grant bus access mechanically. For these
backplanes, you do not need to set switches or jumpers. Bus grants are
provided automatically.
If you are using this type of backplane, make sure the J11 bus grant pass-
through jumper on the Alpha VME 5/352 or 5/480 SBC CPU module is
not installed.
•
Backplanes that use active buffer, OR, NAND, or AND devices
Backplanes that use active buffer OR, NAND, or AND devices may not
work properly with the Alpha VME 5/352 and 5/480 SBC 2-module con-
figuration. These backplane architectures employ active bus grant tech-
niques that do not allow the 2-module SBC to operate as system
controller. In fixed installations, contact your backplane vendor to deter-
mine how to defeat the active grant techniques.
Backplanes that use active buffer devices
For backplanes that use active buffer devices, make sure the J11 bus grant
pass-through jumper on the Alpha VME 5/352 or 5/480 SBC CPU mod-
ule is not installed. In this configuration, the CPU module in slot 1
actively drives the BG_IN_L<3:0> signal of the I/O module in slot 2 to
high as shown in Figure 1–9.
