Fritzing circuit

Hi there,

I have an Adafruit Huzzah Feather project laid out as you can see in the diagram above.

Currently I am having trouble getting it to reliably reset and start the sketch. More often than not I receive garbage in the serial monitor and the sketch doesn't begin.

The baud rate is set to 115200 and when the sketch occasionally I begin to see the expected behaviour and serial messages.

I have done some tests to see if the serial connection is causing a problem. I uploaded a sketch with and without Serial.begin(115200);. Without this the sketch behaves as expected (I'm flashing an LED sequence to know when the loop has begun). When I add serial communication back I get about 50/50 success rate when resetting.

Here are some thoughts about what could be the problem:

  1. A problem with circuitry. Not sure if something is causing the board to occasionally activate the bootloader? After reading some of the FAQs I'm wondering if I'm accidentally pulling a GPIO pin low. However time has been spent making sure the problematic GPIO pins (0, 2 15) aren't being used.
  2. Possible problem with the board itself - but this is unlikely because there are two of them with exactly the same problem.
  3. Problem with the code. (https://pastebin.com/VAEreu6b)

Any thoughts and suggestions are very welcome at this stage.


EDIT: Forgot to add code. Now here: https://pastebin.com/VAEreu6b

  • ... and the code is? – Juraj Feb 27 '18 at 19:33
  • Ah yes! That would be helpful: pastebin.com/VAEreu6b – gfte Feb 27 '18 at 20:33
  • GPIO1 and 3 are used by serial, is there a conflict there? – dandavis Feb 27 '18 at 20:40
  • GPIO1 isn't being used and 3 is connected to an accelerometer using i2c. Would that cause a problem? – gfte Feb 28 '18 at 14:54
  • @gfte yes it is the problem. pin 4 and 5 are default for I2C in esp8266 arduino core. the accelerometer library uses pin 3? – Juraj Mar 2 '18 at 18:25

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