ESP8266 Community Forum

- Mon Apr 23, 2018 5:03 am #75557 A bit late, but I had shelved the project, using the Arilux of the shelf solutions in the interim.
But, now I am reaching the limit of those, and want to get these done. Any comments?

ESP12E_ControlNode.PNG

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- Mon Apr 23, 2018 6:31 am #75558 Add a pull up resistor to RX.

I don't know what conftdi will do but if you will be using I2C then I would also add pull up resistors there. 2K2

- Mon Apr 23, 2018 4:23 pm #75564

Add a pull up resistor to RX.

I don't know what conftdi will do but if you will be using I2C then I would also add pull up resistors there. 2K2

Thanks for the quick feedback rudi, SCL and SDA already have 10k pullups, as I plan to use GPIO02 and GPIO00 respectively for it.


What is the thinking behind the pull up on Rx?

- Mon Apr 23, 2018 10:55 pm #75568

What is the thinking behind the pull up on Rx?

For some reason if RX is not high on boot user code will not run. I can think of a couple of possible reasons but they are just guesses.

A lot of people use boards with usb-serial converters on board. The converter gives the RX pin a high so they don't see the problem. Even if they are not connected to a usb port. (board externally powered) All my boards are without usb converters. I have external ones, and had always been present in development. But then one day I had reason to just run the ESP without a converter attached, and it didn't work. I added the pull up and after that all was happy again. I always include an RX pull up resistor on my board designs.