Power Up Configuration; Figure 2-20. A Typical Example Of A 3-Pin Jumper Strapping Circuit - VIA Technologies Apollo Pro133A Design Manual

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2.2.8 Power Up Configuration

During system restart and power up, system configuration information is latched at the rising edge of the RESET# signal. All
signals used to select power-up strap options are connected to either internal pull-up or pull-down resistors of minimum 50K ohms
(maximum is 150K ohm). These internal resistors select a default mode on the signal during reset. To enable different modes,
external pull-ups or pull-downs (the opposite of the internal pull-up or pull-down) of approximately 10K ohm can be connected to
particular signals. These pull-ups or pull-downs should be connected to the relative (e.g. 3.3V) power supply. For example, a 3-
pin jumper is used to select a pull-up (1-2) or pull-down (2-3) strapping as shown in Figure 2-20. The strapping state of logical 1
or logical 0 can be selected by using a jumper (shortage between pins).
VT82C686A
(South Bridge)
ROMCS#
Preliminary Revision 0.5, November 19, 1999
4.7~10K
C1
ohm

Figure 2-20. A Typical Example of a 3-pin Jumper Strapping Circuit

Design Guide - VT82C694X Apollo Pro133 with VT82C686A
VCC3
JCONF
JCONF
1
2
3
Header 1x3
27
CPU Configuration
1-2 Slot-1 or Socket-370
2-3 Socket-7
Motherboard Design Guidelines