Hi Expert,
I want to use two RMII interface of CPSW to connect with another MAC and external PHY.
As the below figure shown, For the PHY, I plan to use external clock source for the PHY, and use the TDA4VM internal clock source (CLKOUT) for the MAC-TO-MAC connection. Based on the TDA4VM TRM chapter 12.2.2.2.1 description, whatever we use external clock source or internal clock source for RMII interface, we should connect RMII_REF_CLK pin to the peer device.
However, all of TDA4VM RMII interfaces share the only RMII_REF_CLK pin.
The question what I want to ask is :
How to handle the pin of RMII_REF_CLK if we simultaneously use another MAC and external PHY? Do we directly connect them one by one with daisy chain, like the dash line shown in the below figure? If that, how to guarantee the clock is not messy and the data synchronize of RMII1 and RMII2 are correct. Because the REF_CLK phase of PHY output might be different with the MAC-TO-MAC REF_CLK phase.
Another question is about detailed MAC-TO-MAC connection. Could you kindly help me check whether the connection is right, especially for RX_ER? I plan to pull them to ground with resistors.
Thanks a lot~
