No ethernet on some switches

[demoman]

Posted on October 15, 2015 at 10:16

Guys, I have a strange behavior using STM32F373RCT6 with ENC28J60 Ethernet IC:

Overview: The IC is connected to STM controller via SPI. I�ve attached the schematics. It�s configured to half-duplex mode, for compatibility reasons. I�m using UDP protocol to send some data from a PC to the STM. The STM returns an �OK� packet via UDP when it receives the data. Everything works fine if I have a direct connection between the PC and the STM. Problem: The strange thing happens when I connect the PC to the STM via an Ethernet switch: On some ports the communication is working, on some it does not � there is no pattern� at least I cannot find one.

• I�ve tried with different switches (Siemens, TP-Link, HP ProCurve) � no difference.

• I�ve tried with different Ethernet cables (4-wire, 8 wire, crossed) � no difference.

• I�ve tried with different duplex combinations (half, full, auto) � no difference.

Do someone knows what might be the reason?

Or can someone please advise what more to check to identify the reason? If any other info is needed to diagnose the problem, please ask and I�ll provide it. Thanks in advance for the time spent!

J

#stm32f373rct6

[jpeacock]

Posted on October 15, 2015 at 14:02

I came across a similar problem with the EN28J60 when it first came out.  My workaround was to set up gratuitous ARP broadcasts once per second.  I believe the problem has to do with some incompatibility between the EN28J60 and most 10/100/1000 switches (it seems to work fine on just 10Mbit switches).

I also had timing problems running the EN28J60 with STM32F controllers.  The PKTCNT register would occasionally lose the packet count so the driver didn't know how many RX packets remained to be read from the buffer.  You might watch out for that as well, unless it's been fixed in later IC revs. After switching to the EN424J600 replacement the problems disappeared.   Jack Peacock