TM4C123GH6PM: Two different design that about tm4c123x 's GNDX PIN connection.

Jefferey

Genius 13875 points

Part Number: TM4C123GH6PM
Other Parts Discussed in Thread: EK-TM4C123GXL

Dear Expert

Hi Jefferey ,

We found two different design that about tm4c123x 's GNDX PIN connection.

In TM4C123G EVM schematic , GNDX PIN is not connect go GND.

If you refer TM4C123X design guidelines , GNDX pin need connect to GND

Which one is correct ?
If we follow demo board design. Does it have any risks?

Thanks for your comment.

over 8 years ago

0 Sai Reddy over 8 years ago

TI__Mastermind 22580 points

Hello Jefferey,

I have forwarded this post to my colleague. He is on vacation so there might be a delay on repsonse.

Thanks,
Sai

0 Amit Ashara over 8 years ago

TI__Guru**** 244380 points

Hello Jefferey,

Typically the GNDX must be connected to the Ground on the board. I am not sure why the designer has made the edit for the LaunchPad. However it can be tested by a continuity test on the board between GNDX and GND.

0 Jefferey over 8 years ago in reply to Amit Ashara

TI__Genius 13875 points

Dear Amit
Because my customer used the design of LaunchPad so the GNDX did not connect to ground.
Is there any risk to follow this kind of design?
Thanks for your comment.

0 Amit Ashara over 8 years ago in reply to Jefferey

TI__Guru**** 244380 points

Hello Jefferey

I should have more information once I can test it on a board. Did the customer check the crystal oscillation their board?

0 Lisa Ding over 8 years ago in reply to Amit Ashara

TI__Expert 6525 points

Hi Amit,
Customer told us crystal oscillation is working well. Do you need any other information ? thanks,

0 Amit Ashara over 8 years ago in reply to Lisa Ding

TI__Guru**** 244380 points

Hello Lisa

I tested and checked the EK-TM4C123GXL design and the layout, the GNDX pin is connected internally to GND pin. So it should be OK.

0 Lisa Ding over 8 years ago in reply to Amit Ashara

TI__Expert 6525 points

Hi Amit,

I see. You mentioned that GNDX pin is connected internally to GND pin. Do you mean GNDX is connected internally to GND in launchPad layout ? thanks.

0 Amit Ashara over 8 years ago in reply to Lisa Ding

TI__Guru**** 244380 points

Hello Lisa

No. GNDX is not connected to the GND in the layout. I do not have a standalone device where I can verify the same, but looking at the layout it does not seem there is a path on the board.

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TM4C123GH6PM: Two different design that about tm4c123x 's GNDX PIN connection.