ESP8266 Community Forum

- Mon Jan 25, 2016 2:27 pm #39671 You can hook up I2C bus on almost any pins, you just need to provide pins number in the begin() function.
Personally, I'm using GPIO0/GPIO2 since they also need PullUps for boot mode, so perfect for I2C bus too.

Code: Select allWire.begin(0, 2);

But if you don't provide pins, they will be defaulted according to the board variant, Generic is 4/5.

- Mon Jan 25, 2016 3:38 pm #39681 I've used the 1602 LCD with an I2C adapter on NodeMcu Lua and Sming, and it works fine in both.

I also use the 1.8 TFT ST7735 based TFT displays with Sming using SPI and it also works fine.

- Tue Jan 26, 2016 12:29 pm #39749

You can hook up I2C bus on almost any pins, you just need to provide pins number in the begin() function.
Personally, I'm using GPIO0/GPIO2 since they also need PullUps for boot mode, so perfect for I2C bus too.

Code: Select allWire.begin(0, 2);

But if you don't provide pins, they will be defaulted according to the board variant, Generic is 4/5.

Thank you for your reply. But I don't see begin() taking GPIO pins in the function prototype. It only takes optional address of the device.
https://www.arduino.cc/en/Reference/WireBegin
Am I missing something?

I've used the 1602 LCD with an I2C adapter on NodeMcu Lua and Sming, and it works fine in both.

I also use the 1.8 TFT ST7735 based TFT displays with Sming using SPI and it also works fine.

Have you got it working in Arduino or Lua? I am mainly talking about getting it to work in Arduino environment. Regardless which GPIO lines on Node MCU did you connect your SDA and SCL from your LCD? And if you got it working in Arduino, what libraries did you use? And can you share your code? Thanks.

- Tue Jan 26, 2016 12:35 pm #39751

Thank you for your reply. But I don't see begin() taking GPIO pins in the function prototype. It only takes optional address of the device.
https://www.arduino.cc/en/Reference/WireBegin
Am I missing something?

The ESP uses its own Wire-library ( https://github.com/esp8266/Arduino/blob ... re-library ), which does accept those arguments.