Aaeon SBC-590 User Manual page 22

J1. J2 must be set to match the clok ratio of CPU. The chart
below shows the proper jumper setting.
freq ratio = 2.5
freq ratio = 2
freq ratio = 3
freq ratio = 1.5*
* default
J1
1
2
1
2
1
2
1
2
J2
1
2
1
2
1
2
1
2
Chapter 2 Installation 15