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twrk60d100 ethernet

Question asked by David Sherman on Aug 23, 2017
Latest reply on Aug 24, 2017 by David Sherman

Hello, I am using the twrk60d100 with the twr-ser module to use the ethernet.  I have jumpered the boards according to the documentation to use the RMII mode, and I've confirmed that the OSCERCLK is 50 MHz by routing it to PTC3. What is strange is the MDC clock is very jittery and it's far off from the expected value.  If the OSCERCLK is 50 MHz, is this what is meant by the "module clock"?  If I put in a value of 9 in the ENET_MSCR register for the MII_SPEED, the MDC clock is around 4 MHz as I've observed.


The core clock is 100 MHz.


If I put in a value of19, then I get something more like 2.5 MHz for the MDC, but it's still very unstable.  What am I missing?