Remove Ethernet Oscillator on Mod5234 to reduce EMI?

[cbyrne]

The Mod5234 has a 25Mhz crystal that feeds the DAVICOM9161 Ethernet chip. We would like to reduce EMI and our application does not need Ethernet. If we just remove the oscillator, what affect would there be on the DAVICOM to Coldfire interface?

Has anyone removed the 25MHz oscillator, for instance when Ethernet is not used? Did you tie XT1/XT2 clocks to ground?

[pbreed]

That should be fine...

You may also want to set the main processor PLL in spread spectrum mode.
Are you trying to get Class A or Class B?

[greengene]

fwiw, we use the spread spectrum mode on the 5270 and it helped quite a bit.

[cbyrne]

MIL-STD 461, not sure how it compares to Class A/B. Yes, we're going to try the processor's spread spectrum feature. Thanks.