Link status of ethernet on TM4C 129 platform

Gavin Lin1

Hi,

I enabled ethernet feature on TM4C platform and it works as well.

But I have one problem about getting link status.

I use this function to get the link status:

int checkLinkState(void)
{
	return (EMACPHYRead(EMAC0_BASE, 0, EPHY_BMSR) & EPHY_BMSR_LINKSTAT);
}

In normal case, power on device and then plug in ethernet cable, I can get the correct result.

But sometimes I meet one failed case, if I plug in ethernet cable first and then power on device, I can't get the correct result.

In this failed case, I can see the activity of ethernet LED when power on device, I think that means emac function enabled.

I guess that maybe caused by the register has not written, so I also try to call this function several times, but it still can't get the correct result.

Is it the known issue on emac feature? Or is there any solution to fix it?

Does anyone get the idea on my problem?

thanks
Gavin

over 10 years ago

0 Amit Ashara over 10 years ago

TI__Guru**** 244400 points

Hello Gavin,

Did you try with a PHY Reset first in the failed case?

Regards
Amit

0 Gavin Lin1 over 10 years ago in reply to Amit Ashara

Expert 1875 points

Hi Amit

No, I didn't try to reset PHY before.

I check API and I guess there are two ways to reset PHY:

1. EMACReset(EMAC0_BASE)
2. EMACPHYPowerOff() EMACPHYPowerOn()

Which one is the better way to do? Or I'm getting misunderstanding?

thanks
Gavin

0 Amit Ashara over 10 years ago

TI__Guru**** 244400 points

Hello Gavin,

It would automatically be handled by EMACPHYConfigSet. This would be used if your setup is using the internal PHY. Can you please attach the code that you use to initialize Ethernet Controller

Regards
Amit

0 Gavin Lin1 over 10 years ago in reply to Amit Ashara

Expert 1875 points

Hi Amit

After scope EN0LED, I got the root cause is that the connection is not ready and I read the register.

Thanks for your replied and suggestion.
Gavin

0 Amit Ashara over 10 years ago in reply to Gavin Lin1

TI__Guru**** 244400 points

Hello Gavin,

Is it the same Link register that was getting set later?

Regards
Amit

0 Gavin Lin1 over 10 years ago in reply to Amit Ashara

Expert 1875 points

Hi Amit

I guess so.

I treat EN0LED as the real connection status.

I scope EN0LED when reset device and sometimes I find EN0LED pulling up timing getting longer, and I meet the failed case in this moment.

I'm not sure the root cause of longer reset timing, but I try to filter the failed case and workaround it.

Do you have any suggestion?

thanks

Gavin

0 Amit Ashara over 10 years ago in reply to Gavin Lin1

TI__Guru**** 244400 points

Hello Gavin,

Can you try switching OFF prefetch buffer before PHY Configuration. The register is called FLASHCONF and the bit to be set is FPOFF

Regards
Amit

0 Gavin Lin1 over 10 years ago in reply to Amit Ashara

Expert 1875 points

Hi Amit

I also find this known issue for my case:
http://processors.wiki.ti.com/index.php/TI-RTOS_TM4C129_Emac_Issues

In the workaround, it turns off prefetch before PHY configuration and turns on prefetch after emac init.

Should I follow it?

In my case, I modify it in lwIPInit in Lwiplib.c.

thnaks
Gavin

0 Amit Ashara over 10 years ago in reply to Gavin Lin1

TI__Guru**** 244400 points

Hello Gavin

Thanks for finding it. I was searching for the same wiki post. Yes you would need to modify it as part of the lwIPInit. Simple would be to do it in the code after SysCtlClockFreqSet and the test it w/o turning it back ON. If it works then you can put the entire WA.

Regards
Amit

0 Gavin Lin1 over 10 years ago in reply to Amit Ashara

Expert 1875 points

Hi Amit

This workaround is okay for me, so I integrate it into my project.

thanks
Gavin

0 Amit Ashara over 10 years ago in reply to Gavin Lin1

TI__Guru**** 244400 points

Hello Gavin,

The WA I mentioned above is the quick fix WA. Please make sure the full WA is implemented else you may end up with a degraded system performance.

Regards
Amit

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Link status of ethernet on TM4C 129 platform