http://www.esp8266basic.com/oled--lcd-d ... mands.html
page.
Thanks Hamish
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For a 1602 ic2 LCD module, the address must be 27H (39Dec)
For OLED ic2 display the address must be 3CH (60Dec)
You cannot change these addresses from within ESP8266Basic, they are set when ESP8266Basic starts.
When ESP8266Basic starts, it initialises the displays. If they are not connected and powered when ESPBasic boots then they wont work. ie if you are using a breadboard and connect the display then run your program it wont be able to access the displays until you either reboot or power off then on.
If you have devices connected to the D3/SDA line this can stop the ESP8266 from booting correctly . D3 is also the flash button.