AnsweredAssumed Answered

STM32F207 and PHY Micrel KSZ8051RNL

Question asked by brousalis.angelo on Sep 17, 2012
Hello,
I want to use the quite new and very cheap Micrel KSZ8051RNL in RMII mode with STM32F207 in a mid volume design. Looking at Micrel's site I found and errata regarding the 8051 phy with the following note :

RMII hold time. Min required RMII hold time is 7ns, should be 2ns per spec. This applies to the 8051RNL, 8021RNL and 8031RNL when operating in 50Mhz RMII mode

and the following workaround :

delay RMII data from other device or clock out on falling edge to provide hold time

Studying the RMII timing diagrams of both 207 and 8051 is not 100% clear to me if the 207 can tolerate the 7ns timing requirement of the 8051. I'd like to have the opinion of ST experts.  And a second question : is the proposed workaround feasible with STM32 MAC ? How can I clock out on falling edge ?? 

Thanks in advance,

Angelo

Outcomes