ESP8266 Community Forum

- Tue May 19, 2015 7:48 am #17855 I see all mentioning of arduino... If you want to do i2c on esp8266, I don't see what arduino has to do with that.

I think it's quite simple, there appears to be no hardware i2c support on the esp8266, so you're free to use whatever pins you like and run one of the software "bitbanging" implementations on it.

- Tue May 19, 2015 11:04 am #17868

Arduino uses pins A4 and A5 for SDA and SCL .
I am using the above board and wish to comunicate with a BMP180 Pressure/Temp sensor
I do not know which pins to use?
Can anyone point me in the right direction please?

Does this post help?

- Tue May 19, 2015 3:10 pm #17894 It all helps thanks . I note however that in the latest ESP8266-yesterday for Arduino IDE 1.6.4 library Igrr talks about I2C in the readme and uses Wire.begin(0, 2); on ESP-01, else they default to pins 4(SDA) and 5(SCL)..

So in my case it is easier to use pins 6 and 7 so I am playing with "Wire.begin(6, 7);" in setup . It compiles OK and uploads to the board but I have not got it reading the BMP180 yet.

Get you modules here:

https://www.banggood.com/custlink/KvGGhGF4wG

- Tue May 19, 2015 3:49 pm #17897 @tytower, check my post at viewtopic.php?f=28&t=2991#p17753
you can either continue to use the deprecated Wire.pins or applying the fix I did in Wire.cpp :

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