IDT 89EBPES16T4G2, Руководство пользователя

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IDT Installation of the EB16T4G2 Eval Board
EB16T4G2 Eval Board Manual 2 - 2 October 3, 2007
Notes
If the Clock Spread Spectrum is used to modulate data rate, then both ports must use same modulated
clock source. Therefore, if your system uses SSC, the on-board clock generator must be disabled and the
upstream reference clock should be used instead.
The output of the onboard clock generator is accessible through two SMA connectors located on the
Evaluation Board. See Table 2.4. This can be used to connect a scope for probing or capturing purposes
and cannot be used to drive the clock from an external source.
Power Sources
The EB16T4G2 and all downstream ports are powered from the upstream port slot power. If add-in
cards require more power than the upstream slot can support, an external source is required to supply this
extra power via an auxiliary 4-pin power connector on the board. Header W1, W2, and W3 (see Table 2.14)
are used to select proper power source for the switch and all downstream ports.
External Power Source
If necessary, external power is supplied to the EB16T4G2 board through a 4-pin auxiliary power
connector attached to J1. The external power supply pr12V to the EB16T4G2 as described in Table
2.5. The +5V is unused.
Clock Frequency Switch - S2[2:1]
S2[2] S2[1] Clock Frequency
OFF OFF Reserved
OFF ON 125 MHz
ON OFF 100 MHz (Default)
ON ON <Reserved>
Table 2.2 Clock Frequency Selection
Clock Spread Spectrum Switch - S2[4:3]
S2[4] S2[3] Spread%
OFF OFF No Spread (Default)
OFF ON Down -0.75
ON OFF Down -0.50
ON ON Center ±0.25
Table 2.3 Clock Spread Spectrum Selection
Onboard Reference Clock Output (Differential) – J7, J6
J6 Positive Reference Clock
J7 Negative Reference Clock
Table 2.4 SMA Connectors - Onboard Reference Clock