ADLINK PCIS-8580-13S - Manual (Page 24)

16 Hardware Overview
adopts a spread-spectrum clock generator to help user to deal
with this difficult task.
Spread spectrum clocking speeds up and slows down the clock
within a few percent of its fundamental frequency. By reducing
the peak amplitudes, the system will more likely meet EMI
emission compliance standards. In other words, spread spec-
trum clocking distributes the energy that was originally concen-
trated on one frequency over a wider band. This method
dramatically reduces the amount of EMI.
M66EN Setting, JP2
LPCI-8575 supports 32-bit PCI buses operating at 66MHz or
33MHz. A bundled link can support the full bandwidth of 32-bit/
66MHz PCI bus. You can utilize the following configuration to
set the operation frequency of your system.
Spread Spectrum Control JP1
OFF (default)
ON
Table 3-2: JP1 Settings
JP2 Setting
Auto detection mode enabled. When LPCI-8575 is plugged
into system slot in the extended chassis, it will detect the con-
figuration and operate at 33MHz or 66MHz automatically. If
the backplane or any devices in the system do not support
66MHz PCI bus operations, LPCI-8575 will only operate at
33 MHz only.
Table 3-3: JP2 Settings