RTOS/TM4C129ENCPDT: Custom Ethernet circuit not working

Asif Ali83

Part Number: TM4C129ENCPDT
Other Parts Discussed in Thread: EK-TM4C129EXL

Tool/software: TI-RTOS

Hi,

I have tested the udpecho example code incuded in the TI-RTOS examples and it is working fine on my EK-TM4C129EXl board. Issue is it is not working on the custom board. MAC address is updated successfully. My circuit is shown in fig. What are the possible mistakes?

Thanks

over 6 years ago

0 Genatco over 6 years ago

Guru 55913 points

Hello,

J34 would be prime suspect check datasheet listing two proven transformers. Search of forum you will find scope captures of working/nonworking differential pairs signals. You can also perform a simple loopback test, check EMAC0 datasheet for register programming.

0 Charles Tsai over 6 years ago

TI__Guru**** 191366 points

Hi,
Like BP101 suggested, please refer to the TM4C129 System Design Guideline about the transformer and ESD protection for the Ethernet interface. Please go to section 4.1. www.ti.com/.../spma056.pdf

0 Asif Ali83 over 6 years ago in reply to Genatco

Prodigy 120 points

Thank you BP101,

Thank you for the reply, i will work on it. if possible give some links for 'scope captures of working/nonworking differential pairs signals'.

0 Asif Ali83 over 6 years ago in reply to Charles Tsai

Prodigy 120 points

Thanks Charles,
Why is it not supporting the inbuilt Mag and transformers?

0 Charles Tsai over 6 years ago in reply to Asif Ali83

TI__Guru**** 191366 points

Hi Asif,
Transformer is required as part of the standard. Please see below two links that maybe helpful.

networkengineering.stackexchange.com/.../what-is-the-purpose-of-an-ethernet-magnetic-transformer-and-how-are-they-used
electronics.stackexchange.com/.../why-are-ethernet-rj45-sockets-magnetically-coupled

0 Genatco over 6 years ago in reply to Asif Ali83

Guru 55913 points

Asif Ali57 said:
if possible give some links for 'scope captures of working/nonworking differential pairs signals'

Some posters in forum have made embedded XFMR types work with TM4C1294 and list part numbers. You have to do your own searches; try Ethernet, PHY or other key words MAG, magnetic/s etc...

0 Asif Ali83 over 6 years ago in reply to Charles Tsai

Prodigy 120 points

Hi,

Thank you, and I know the purpose of mag transformers in the ethernet circuits.

I am trying to develop a custom board and I have used the same circuit of launchpad EK-TM4C129EXL , just replaced the mag transformers,tvs diode array, RJ45 connector with the '5-6605425-1' which has inbuilt mag transformers and circuits. The specification of transformers HX1198FNL ( used in launchpad) 5-6605425-1(custom board)are compatible.The firmware is tested with launchpad, but not working in custom board. This is the issue I am facing.

Regards

0 Charles Tsai over 6 years ago in reply to Asif Ali83

TI__Guru**** 191366 points

Hi,
Please take a look at the below thread where a TI reference design uses a RJ45 connector with the built-in transformer. You can compare yours with the schematic of the reference design.

e2e.ti.com/.../2587587

0 Charles Tsai over 6 years ago in reply to Charles Tsai

TI__Guru**** 191366 points

Hi,
I will close this thread for now. If you have questions you can reopen this thread or open a new thread.

0 Asif Ali83 over 6 years ago in reply to Charles Tsai

Prodigy 120 points

Thank Charles,

The link you shared is great for me.

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RTOS/TM4C129ENCPDT: Custom Ethernet circuit not working