MCF54417 RMII

[bplatt]

Processor:  MCF54417

I am tasked with troubleshooting someone else's MCF54417 RMII design.  We seem to be losing connectivity intermittently.

Attached is the layout.  I am wondering the pull-up and pull-down resistors on RMII_CRS_DV are correct?  There is a pull-up on RMII0 and a pull-down on RMII1?  Any other external components missing?

Please advise.

[miduo]

Hello,

Well, from the hardware schematic, I do not think that the pull-up/pull-down is a issue. Actually as mentioned by the datasheet of KSZ8081RNA that:

"The PHYAD[1:0] strap-in pin is latched at the de-assertion of reset. In some systems, the RMII MAC receive input pins may drive high/low during power-up or reset, and consequently cause the PHYAD[1:0] strap-in pin, a shared pin with the RMII CRS_DV signal, to be latched to the unintended high/low state. In this case an external pull-up (4.7 kΩ) or pulldown (1.0 kΩ) should be added on the PHYAD[1:0] strap-in pin to ensure that the intended value is strapped-in correctly."

So my query is for software driver, do you config the PHY driver correctly? We only provide the DP83849I driver with TWR-MCF5441X.