AOpen AX5T-TBL User Manual

Appendix A

Jumper Table Summary

Setting the CPU Voltage

JP11

1-2
3-4
5-6
7-8
9-10
11-12

CPU Core Voltage (Vcore)

3.45V (Intel P54C)

3.52V (Cyrix or AMD K5)

2.9V (AMD K6-166/200 or Cyrix M2)

2.8V (MMX P55C)

3.2V (AMD K6-233)

2.5V/2.2V/2.0V (Reserved)

Warning: Please make sure that you have installed CPU fan
properly if Intel PP/MT-233 or AMD K6-200/233 is being
selected to use. It may cause your system unstable if you can
not meettheheat dissipation requirement from above CPUtype.
It is recommended to adopt larger fan on these CPU for better
air flow in the system.

Tip: Normally,for singlevoltage CPU, Vcpuio(CPU I/O Voltage)
is equal to Vcore, but for CPU that needs dual voltage such as
PP/MT (P55C) or Cyrix 6x86L, Vcpuio is different from Vcore
and must be set to Vio (PBSRAM and Chipset Voltage). The
single or dual voltage CPU is automatically detected by
hardware circuit.

Tip: JP11 pin 11-12 is reserved for future CPU, the most
possible value is 2.0V. It is not yet decided when this manual is
printed. Use voltage meter or check your distributor before you
use pin 11-12.

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Jumper Table Summary

CPU Type JP11 Vcore Vio Vcpuio

INTEL P54C Single Voltage 1-2 3.45V 3.45V Vcore
INTEL MMX P55C Dual Voltage 7-8 2.8V 3.45V Vio
AMD K5 Single Voltage 3-4 3.52V 3.45V Vcore
AMD K6-166/200 Dual Voltage 5-6 2.9V 3.45V Vio
AMD K6-233 Dual Voltage 9-10 3.2V 3.45V Vio
Cyrix 6x86 Single Voltage 3-4 3.52V 3.45V Vcore
Cyrix 6x86L Dual Voltage 7-8 2.8V 3.45V Vio
Cyrix M2 Dual Voltage 5-6 2.9V 3.45V Vio

Selecting the CPU Frequency

JP3

1-2
1-2
1-2
1-2
2-3
2-3
2-3
2-3

JP2

1-2
1-2
2-3
2-3
1-2
2-3
2-3
1-2

JP1

1-2
2-3
2-3
1-2
2-3
2-3
1-2
1-2

CPU

Frequency
Ratio

1.5x (3.5x)
2x

2.5x (1.75x)
3x
4x

4.5x
5x

5.5x

JP4

1-2
2-3
2-3
1-2

JP5

2-3
2-3
1-2
1-2

JP6

1-2
1-2
1-2
2-3

CPU
External
Clock

60MHz
66MHz
75MHz

83.3MHz

Warning: INTEL TX chipset supports only 60/66MHz
external CPU bus clock, the 75/83.3 MHz settings are for
internal test only, set to 75/83.3MHz exceeds the
specification of TX chipset, which may cause serious
system damage.

Note: Intel PP/MT MMX 233MHz is using 1.5x jumper
setting for 3.5x frequency ratio, and AMD PR166 is using

2.5x setting for 1.75x frequency ratio.

Warning: Cyrix 6x86 P200+ uses 75MHz external clock,
the jumper setting shown on the table below is for user's
convenient. It may cause serious system damage to use
75MHz clock.

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