ESP8266 Community Forum

- Wed Sep 09, 2015 10:54 am #28714

http://reflowster.com/blog/2015/05/11/esp8266.html
will give you an idea

yes, thank you. I have seen this example before. however, it is a rough idea on how to program it. I can understand that part. What I am interested in is how to use GPIO0 and GPIO2 and tie it to an i2C device at the same time. What escapes me is how add whatever is needed. I am afraid I don't get the whole pull down, pull up.

I will start with this drawing and get it operational. I could use help getting the I2C connections added to the diagram.

- Wed Sep 09, 2015 11:47 am #28719 Simply make sure that you have PullUps on both GPIO2/GPIO0, then can you use those as an I2C Bus, attached to MCP23017 for example. In the code, your will have Wire.begin(0, 2); to initialize I2C.

If your question is how to have DTR connected to GPIO0 to avoid pulling it HIGH permanently, either you add a diode between DTR and I2C bus, or use a MOSFET with the same connection as a level shifter.

- Wed Sep 09, 2015 11:53 am #28720

Simply make sure that you have PullUps on both GPIO2/GPIO0, then can you use those as an I2C Bus, attached to MCP23017 for example. In the code, your will have Wire.begin(0, 2); to initialize I2C.

If your question is how to have DTR connected to GPIO0 to avoid pulling it HIGH permanently, either you add a diode between DTR and I2C bus, or use a MOSFET with the same connection as a level shifter.

ok, I will do my best to diagram this. Having reviewed more this AM, I see that I have CTS not RTS on my FTDI chip. Are they the same and can I use CTS to connect to RESET on ESP8266-01 chip? if so, how.

I will then volunteer to test and publish what I got working.

(just a note that I have this working on ESP8266-12 but using other pins, just trying to get one circuit built to do this universally)