Programmable Devices
CPLDs, FPGAs, SoC FPGAs, Configuration, and Transceivers
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About problem with using EMAC splitter and GMII_TO_RGMII

Honored Contributor II


I am newer. 

One of EMAC in HPS is being used by the construction with the pin of FPGA. 

The design of the hardware is reference of the following site. 


When I tried to do ping test by using WindowsPC, I confirmed it worked fine in 10Mbps(Full/Half), 1000Mbps. 

But It failed only at 100Mbs. 

So I have investigated now, and I did following procedure, 


  • Set the ctrl register of System Manager(0xFFD08060) to “1” (RGMII). 


It works fine. It passes ping test at 10Mbps, 100Mbps and 1000Mbps. 

But I do not understand why? 

I think that EMAC may be connected to GMII_TO_RGMII IP package. 

So the value of ctrl register of System Manager(0xFFD08060) shall be “0”(GMII). 

Please tell me why? 



Best Regards, 

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