ESP8266 Community Forum

- Sun May 17, 2015 2:30 pm #17684 that serial thing is fixed, but the changes have not yet been pulled into the main repo,so sit tight, find other bugs and report I imagine Ivan will pull them when he's back from wherever he is Your I2C should be fine with what you are currently running.

- Mon May 18, 2015 10:08 am #17753 Hi ficeto,
I gave it a try and it is much better.
No more watchdog crash on SerialRX.
But I saw that I2C was still not working.
But I've figured out something : if I use the now deprecated Wire.pins(12,13), it is actually working. So the problem is somewhere is the newer Wire.begin(12, 13).
I will dig further ...

EDIT : some digging done !
I've changed the follwing code :

Code: Select allvoid TwoWire::begin(int sda, int scl){
+  default_sda_pin = sda;
+  default_scl_pin = scl;
  twi_init(sda, scl);   
  flush();
}


it sounds like there is a call to TwoWire::begin(void) after TwoWire::begin(int sda, int scl), which overwrite the previous pins.
Anyway, I have now that workaround...

EDIT2: It is a false positive, it is working after upload, but if I do a reset, it stop working. Really strange
(I think I will have to revert again to the March 27 version)
EDIT3: The constructor issue and the stop after reset issue are separate, after power cycle, it is working again.

- Tue Aug 09, 2016 2:27 pm #52584 Hello martinayotte,

I'm using the nodemcu v3 development board and I had trouble using any gpio to talk via i2c with an adxl345. My question is if inserting that function in the wire.cpp file will do the trick so that now I can call wire.Begin(16,14) as my SDL and SCL pins? Is that correct? I'm using Arduino IDE 1.6.5 with the ESP8266 2.1.0 package as the board manager.

Thanks for your help!

- Tue Aug 09, 2016 7:53 pm #52602 The above bug was a year ago, it have been fixed a while ago.
It was also already fixed in 2.1.0, so I don't understand why you would have any issue.
The problem is probably somewhere else ...
Did you added PullUps resistors on the I2C bus ?
Don't rely in weak internal pullups, they are weak, especially in your case, GPIO16 doesn't have any internal pullup.