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LPC4357: Ethernet not working because unable to read/write RMII (custom board)

Question asked by uaz on Jun 7, 2018
Latest reply on Jun 8, 2018 by jeremyzhou



I'm currently working on a custom board using LPC4357.

At the moment, I'm stuck with Ethernet driver development. I ported LPCopen drivers to Crossworks IDE.


1. My current problem is that if I try to read/write using Chip_ENET_StartMIIWrite() or Chip_ENET_StartMIIRead(), my program will get usagefault with INVSTATE bit set.


2. If I step in the program, I manage to write to MAC_MII_ADDR register without getting usage fault. But I found that GB bit of MAC_MII_ADDR is always 0 and can never be set to 1. Might this be the reason why I get usage fault?


3. I checked the MDC line using oscilloscope, but I don't see any clock signal even though I configured the "CSR clock range" of MAC_MII_ADDR register.


Anyone has any idea of what is going on? My JTAG connection also crashes a lot during debugging.