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I have designed and manufactured a PCB which contains an ESP8266 (ESP-WROOM-02D) chip with the serial uart pins connected to a 30pin connector. I made a mistake on the layout (first time designing a PCB), and have the RX (Pin 3) and TX (pin 1) pins connected incorrectly (swapped).

Is there a way to switch these pins in software? There's no nice way to physically modify and I was hoping to not have to have the boards manufactured again if I can avoid it.

Thanks!

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    no. there is not
    – Juraj
    Aug 17, 2021 at 5:30

1 Answer 1

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You could potentially still fix this by using SoftwareSerial.
Instead of using the hard-wired serial, you can create one in software and use any pins you'd like... Have a look at this github project.
This work-around however requires you to have two unused pins to assign to SoftwareSerial.

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  • the linked SoftwareSerial library is bundled with esp8266 Arduino boards support package
    – Juraj
    Aug 17, 2021 at 9:21
  • Can I reassign the two hardware serial pins to software serial? It is hardwired to pins 1 and 3...
    – tommy-b-10
    Aug 17, 2021 at 10:14
  • @tommy-b-10, how do you flash the sketch into the esp?
    – Juraj
    Aug 17, 2021 at 15:37
  • @Juraj I flash the initial sketch before the esp is soldered to the board, then future flashes are done OTA using the esp wifi.
    – tommy-b-10
    Aug 18, 2021 at 5:02
  • Had another crack at this and realised I needed to set the pinmode to function_3 for pins 1 and 3 before calling softwareserial.begin. Works perfectly now! Is there any downsides to using softwareserial? I have it working at 115200 baud but a little concerned about stability. Cheers!
    – tommy-b-10
    Aug 19, 2021 at 7:21

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