DP83TG720EVM-MC: DHCP(IP) connection waits for a long time

JIM SHEN

Part Number: DP83TG720EVM-MC

Tool/software:

We found that on UBUNTU, the network is always connected when the SPE cable is removed.

However, when the SPE cable is connected, obtaining an IP address from the DHCP server takes about 3–5 minutes before the network is available.

If we manually disable and then re-enable the LAN after connecting the SPE cable, the IP acquisition process speeds up.

Would it be possible to modify the firmware so that the network is disabled when the SPE cable is removed and enabled when the SPE cable is inserted?

7 months ago

0 Drew Miller1 7 months ago

TI__Mastermind 36933 points

Hi Jim,

The link stays up because the standard Ethernet connection between the Ubuntu system and the DP83TG720EVM-MC remains up when SPE cable is disconnected.

I'd recommend continuing to either force link down up or request new DHCP lease. You might find the resource below helpful.

https://serverfault.com/questions/42799/how-do-i-force-linux-to-reacquire-a-new-ip-address-from-the-dhcp-server

Thanks,

Drew

0 JIM SHEN 6 months ago in reply to Drew Miller1

Prodigy 80 points

hi Drew

This is an issue from our customer. The customer requests us to modify the firmware so that the network is disabled when the SPE cable is removed and enabled when the SPE cable is inserted.

So, can you fix the firmware?

PS: Since the board we newly designed for the customer, based on the DP83TG720EVM-MC EVM, also has the same issue.

0 David Creger 6 months ago in reply to JIM SHEN

TI__Mastermind 27212 points

Hi Jim,

Your Ubuntu OS will detect a link up based on the link status of the standard ethernet PHY onboard. This is unrelated to the link status of the single pair ethernet PHY DP83TG720.

DP83TG720EVM-MC is intended to be used out of the box and firmware cannot be modified.

On your new design some logic could theoretically be added to drop link of the industrial PHY based on the link status of the single pair ethernet PHY.

Thanks,

David

0 JIM SHEN 6 months ago in reply to David Creger

Prodigy 80 points

hi Drew

On your new design some logic could theoretically be added to drop link of the industrial PHY based on the link status of the single pair ethernet PHY. -----> Is there a reference wiring diagram for disconnecting a single pair of Ethernet?

0 Drew Miller1 6 months ago in reply to JIM SHEN

TI__Mastermind 36933 points

Hi Jim,

Is it possible to connect DPTG720 link status (LED0) to DP83867 PWDN?

Thanks,

Drew

+1 JIM SHEN 6 months ago in reply to Drew Miller1

Prodigy 80 points

hi Drew

thank you

Can execute

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DP83TG720EVM-MC: DHCP(IP) connection waits for a long time