AM335x MII interface with Lan8710i issue

Jason Z

Intellectual 560 points

Other Parts Discussed in Thread: AM3352

HI,

Dear Sir and Madam,

I am using LAN8710a and AM3352 for one of our products ,which is starting for mass production,

but there is an issue or concern found , which is really needed to fix ASAP. the details are as follows.

Most time, it is working fine and stable, just sometimes especially when power on or when unplug and plug back the RJ45 cable from the POE connector , the PHY dosen't work any more.I don't know if the PHY is damaged or some configuration is wrong , can you give me some advice ASAP? the schematic is as follows.

BTW, from EMC ,EMI and safety perspective, how to improve my current design, add more RC ?

also the 22R serial resisters is needed to change to 100R? Can I leave the Pin18(nINT/TXER/TXD4) open ? what is the different between

config to nINT mode and TXER/TXD4 if I am using MII?

Appreciate for you reply ASAP!

Cheers,

Jason

over 11 years ago

0 Biser Gatchev-XID over 11 years ago

TI__Guru**** 393215 points

Hi Jason,

Regarding the nINT please check this post: http://e2e.ti.com/support/arm/sitara_arm/f/791/t/71743.aspx.

You say the PHY stops working. Does it recover afterwards? It isn't clear from your post. Other than that your connections seem OK on the AM335X side. On the Ethernet side, the LAN8710 is not a TI product. You should refer to the manufacturer's web site for design guidelines.

0 Jason Z over 11 years ago in reply to Biser Gatchev-XID

Intellectual 560 points

it won't recovery even after reset, it seems the PHY going into some state hanging, I don't know how to clean it and bring it to normal, I saw someone mentioned that the there is a bug in Uboot or linux drive regarding the Auto MIDx ,which is causing this issue, can you confirm it?

Cheers,

Jason

0 Jason Z over 11 years ago in reply to Jason Z

Intellectual 560 points

also, I am using separate reset circuit , both of them are STM809, is it causing some potenrial issue?

Appreciated your reply!

Jason

0 Biser Gatchev-XID over 11 years ago in reply to Jason Z

TI__Guru**** 393215 points

Don't you use a GPIO from the processor to drive the PHY reset?

0 Jason Z over 11 years ago in reply to Biser Gatchev-XID

Intellectual 560 points

Hi Biser,

I am using a dedicated reset circuit to connect to the reset of Lan8710 rather than connecting to the GPIO of the processor , you can check my previous attached schematic. is it an problem, what's the right way to do ?

Thanks,

Jason

0 Keldy over 11 years ago in reply to Jason Z

Expert 1835 points

Hi Jason,

I'm facing the same issue like you did, I'm also using the LAN8710 PHY. the PHY chip gone after PoE plug and unplug several times.

Have you solve the problem?

Regards

Keldy

0 Ricardo Urbano over 10 years ago in reply to Keldy

Prodigy 10 points

HI Jason,

Can you please share your findings?. I have a similar issue with my Ethernet.

Thanks,

Ricardo

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AM335x MII interface with Lan8710i issue