CPU Clock (JP5, JP6, JP7)
The system board is fitted with a clock generator that allows you to
choose a different CPU frequency simply by changing the jumper
settings. The following clock frequencies apply to the listed CPU type:
CPU Type
CPU Clock Freq.
486SX-25
25MHz
486SX-33
33MHz
487SX-25
25MHz
487SX-33
33MHz
486DX-33
33MHz
486DX-40
40MHz
486DX-50
50MHz
486DX2-50
25MHz
486DX2-66
33MHz
OVERDRIVE-25
25MHz
OVERDRIVE-33
33MHz
When you change the CPU type, select the proper CPU clock speed by
changing the settings of JP5, JP6 and JP7 jumpers according to the above
table. The setup depends on installation of U6 or U7 as shown below
CPU
Clock
MX8315/UM9515 (U7) Installed
IMISC466 (U6) Installed
JP5
JP6
JP7
JP5
JP6
JP7
25 MHz
Open
Open
Short
Open
Open
Open
33 MHz
Short
Short
Short
Short
Short
Open
40 MHz
Open
Short
Short
Open
Short
Open
50 MHz
Short
Open
Open
Short
Open
Open
Power Management Mode Control (JP13)
There are four power management modes in the system board: Normal,
Doze, Standby, and Suspend. By connecting JP13 to a control switch on
the front panel of the system case, you can directly trigger the system
2-4
Manual No. 771924-D03, Mar. 1995
MGI486 System Board User's Guide
