MCB2300: RMII CLOCK ON PINCORRECT

Information in this article applies to:

• MCB2360 Evaluation Board Version 3.0
• MCB2370 Evaluation Board Version 3.0
• MCB2360 Evaluation Board Version 3.1
• MCB2370 Evaluation Board Version 3.1

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

• DP93949I PHYTER National Semiconductor Data Sheet

FORUM THREADS

The following Discussion Forum threads may provide information related to this topic.

• ethernet schematic

Last Reviewed: Tuesday, October 23, 2007