Specifications

PENTIUM® PRO PROCESSOR AT 150, 166, 180, and 200 MHz E
86
Socket 8
UP#
+ 5 Volt
10 k
Ω
Header 8
Figure 51. Upgrade Presence
Detect Schematic—Case 1
• Case 2:
Header 8 AND alternate voltage source
i
f the system is designed with alternate voltage
source and a Header 8 for future upgrade
support, then the UP# signal must be connected
between Socket 8, Header 8, and the alternate
voltage source. The Pentium Pro Voltage
Regulator should use the UP# signal to disable
the voltage output when detected low (indicating
that an OverDrive processor has been
installed). The OverDrive VRM, when installed
into the Header 8 will use the UP# signal to
enable its outputs (when detected low). When
the Pentium Pro processor is replaced with an
OverDrive processor and the OverDrive VRM is
installed, the original voltage regulator must
never enable its outputs because the lower
voltage OverDrive processor could be
damaged. Refer to Figure 52.
On-Board VR
Socket 8
UP#
+ 5 Volt
10 k
Ω
Header 8
Figure 52. Upgrade Presence
Detect Schematic—Case 2
• Case 3: Alternate voltage source only
If the system is designed with only a
programmable voltage source using the VID3-
VID0 pins, then the UP# signal need not be
used.
NOTE
The programmable voltage source needs to
be able to provide the OverDrive processor
with its required power. Refer to Figure 53.