RX1010 fails to boot when listening to UART

[Nate_PCS]

I'm running into issues with UART on the MIMXRT1010-EVK board.
When i connect a FTDI cable (3.3V) to the following pins:
Connected FTDI TX to J56 pin 2 (LPUART1_RXD)
Connected FTDI RX to J56 pin 4 (LPUART1_TXD)
connected a shared ground

I see this behavior:
When FTDI TX is connected the dev board has issues booting (device enters into maintenance mode).
if TX is removed it boots fine (also see the bootup hello world output).
Note: I used the standard "hello_world" example from NXP.

I need this solved for two reasons:
1) I'd love to use the dev board as part of my testing
2) If this is a issue in a simplified solution (just the RT1011) then I'll need to change parts. The sooner I know this the better.

Thanks!
Nate

[jeremyzhou]

Hi,
Thank you for your interest in NXP Semiconductor products and for the opportunity to serve you.
Please follow the below steps to set the hardware connection.
1) Removes the jumpers on the J31 and J32;
2) Connects FTDI TX to J56 pin 2 (LPUART1_RXD) and FTDI RX to J56 pin 4 (LPUART1_TXD), meanwhile connects a shared ground(as the figure shows);

3) Power on the EVK board;
4) Plug the FTDI into the USB port on the PC;
5) Click the SW9 to reset the MCU to make the MCU boot up again.
After that, you can see the outputted string and it works well on my board.
Have a great day,
TIC

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[Nate_PCS]

Thanks I also realized that the debug USB also comes up as COM so i can get access via testing that way as well.

However I still have one pending question:

Why does a reset of the board need to occur after the FTDI cable is installed? Our product will be using a UART solution and I want to make sure that our chip doesn't come up in a bad state on bootup in our custom PCB.

Thanks for the help!

Nate

[jeremyzhou]

Hi，
Thanks for your reply.
1) Why does a reset of the board need to occur after the FTDI cable is installed?
-- Actually, the step is not necessary, it's used to make the MCU reboot to print out some string to confirm the hardware connection is good.
Have a great day,
TIC

-------------------------------------------------------------------------------
Note:
- If this post answers your question, please click the "Mark Correct" button. Thank you!

- We are following threads for 7 weeks after the last post, later replies are ignored
Please open a new thread and refer to the closed one, if you have a related question at a later point in time.
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[Nate_PCS]

OK Thank you!

When I have the chance I'll give your steps a shot as it will validate how we plan on using the RT1010 in our final solution.

I appreciate your work and will mark it as the answer after I've tired it out.

Nate