ESP8266 Community Forum

- Fri Oct 27, 2017 2:15 pm #71277 Hello,

using a nodemcu, I just managed to make my 20x4 lcd working, but there is no dsa/scl on any pinout chart I found on the web

(I got it working usin sda on D2 and scl on D1 from a tutorial)

is there no official documentation for this ? is the official arduino lcd library using these pins as default for bigbanged i2c protocol ?

thanks

- Sat Oct 28, 2017 8:12 am #71308 It is not defined in lcd lib but in board definitions.
For esp-01 it is gpio0/2 for obvious reasons, for others it is gpio4/5 I think.

- Sat Oct 28, 2017 10:51 am #71313

is there no official documentation for this ?

Of course there is. You just need to look for it.

https://github.com/esp8266/Arduino/blob ... re-library

https://github.com/esp8266/Arduino/blob ... Wire.h#L53

- Sun Oct 29, 2017 9:10 am #71341 There's even a nice picture in our Wiki.



Because the ESP doesn't have hardware I2C support, it's not in the above list, like for instance SPI is.
But... normally GPIO4 (SDA) and GPIO5 (CLK) are used for I2C.

Assumption is the mother of all f*ckups. At least: that's what I'm assuming.