ARM Technical Support Knowledge Articles

RMII CLOCK ON PINCORRECT

Applies to: MCB2300 Evaluation Board

Answer


Information in this article applies to:


PROBLEM

National Semiconductor DP93949 product specialists have analyzed that the 25MHz clock out pin should not be used for RMII Ethernet clock reference on LPC23xx pin P1.15.

CAUSE

The 25MHz_OUT signal is a delayed version of the X1/REF_CLK input. While this clock may be used for other purposes it should not be used as the timing reference for RMII control and data signals.

SOLUTION

Connect the 50MHz signal on X1 directly to the RMII Ethernet clock reference on LPC23xx pin P1.15.

MORE INFORMATION

ATTACHED FILES

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Article last edited on: 2007-10-23 05:33:09

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