User`s manual

12 PCA-6155V User's Manual
Table 1-3: CPU clock ratio selection (JP12)
1.8.2 CPU external (bus) frequency selection (JP3)
These jumpers tell the clock generator what frequency to send to the
CPU. These allow the selection of the CPU's external frequency (or
bus clock). The CPU's external frequency multiplied by the CPU clock
ratio equals the CPU's internal frequency (i.e. the advertised CPU
speed).
Table 1-4: CPU external (bus) frequency selection (JP3)
1
3333
1112222
4444
55 60 66 75MHz MHz MHz MHz
1
3
5
2
4
6
1
3
5
2
4
6
1
3
5
2
4
6
1
3
5
2
4
6
1
3
5
2
4
6
1
3
5
2
4
6
1.5x 2x 2.5x
3x 3.5x 4x