AWR1843BOOST: UART Pull Up Resistors

user4830157

Part Number: AWR1843BOOST
Other Parts Discussed in Thread: AWR1843, TM4C1294NCPDT

Hello,

We are using an AWR1843Boost and our custom build board for AWR1843. We have observed that both boards UART lines are already pulled up without the need for external pull up resistors. In both boards, we are using TM4C1294NCPDTI3R for the UART communication. Can you please answer my following questions?

Does TM4C1294NCPDTI3R have an internal pull up resistors for the UART?
If yes then, how can we disable them and relay only on the external ones provided on the board?

We are tried to solder the 0R resistors for the UART on the AWR1843Boost to establish UART communication from the FTDI chip on the DCA1000, but this leads to wrong communication because the FTDI chip is not able to pull down the Rx line. Do you have any suggestions?

Thanks.

over 5 years ago

0 Cesar over 5 years ago

TI__Guru*** 149204 points

Hi,

The mmwave team does not support the part TM4C1294NCPDT.

I have assigned this thread to another team

thank you

Cesar

0 Vivek Dham over 5 years ago

TI__Guru 58035 points

Hello ,

I am not sure if the TM4C129 has internal pulls , but if your concern is mainly to get the UART communication working with FTDI, for that you need to disconnect the UART lines (remove 0ohms) from the TM4C129. Can you confirm if you have done that?

Regards,

Vivek

0 user4830157 over 5 years ago in reply to Vivek Dham

Intellectual 370 points

Hi Vivek,

Yes, if we disconnect the 0 ohms resistors from the UART line on the TM4C129, then the UART communication is established using the FTDI chip on DCA1000 board. We are sure that the TM4C129 has internal pullups because we removed the pullups on the board. Then we measured the voltage of the UART lines on the TM4C129 and it is indeed 3.3V all the time.

Thanks

0 Vivek Dham over 5 years ago in reply to user4830157

TI__Guru 58035 points

Hello,

Thanks for confirming that the connection works when you disconnect the lines from TM4C129 device. I hope this resolved your issue.

Regards,

Vivek

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AWR1843BOOST: UART Pull Up Resistors