Soyo P55C User Manual

Introduction 5
Remarks on the Cyrix and IBM P200

CPUs

Please note that if you use a Cyrix or IBM P200

CPU, you will have to set the

frequency  to  75MHz.  You  will  also  have  to  set  JP16,  the  PCI  bus  frequency
jumper  to  asynchronous  to  have  the  PCI  bus  run  on  32MHz,  in  order  to  avoid
problems  with  add-on  cards.  If  you  choose  to  run  the  PCI  bus  on  a  higher
frequency, please  use only  high-end add-on  cards that  are specified  to  function
on higher bus frequencies. Please note that using a 75MHz bus clock also places
higher  demands  on  the  DRAM  main-memory,  therefore  only  use  high-end
SIMM/DIMM modules when this is the case.

Voltage settings list

Jumpers 30, 31 and 32 set the processor voltage. If you are using a single voltage
processor close jp31 and open jp30. Jp31 shorts the processor Vcore voltage pins
to the Vio pins when closed. If you use a dual voltage CPU, open jp31 and close
jp30.

Jp 32 sets the voltage, please refer to the following table:

voltage

JP32

1-2

3-4

5-6

7-8

3.5V

3.4V

open

3.3V

open

3.2V

open

3.1V

open

3.0V

open

2.9V

open

2.8V

open

2.7V

open

2.6V

open

2.5V

open

2.4V

open

2.3V

open

2.2V

open

2.1V

open

2.0V

open