ESP8266 Community Forum

- Mon Jan 30, 2017 12:20 am #61751 Hi,

Thank you so much for your message.

Master side:
Wire.begin(0, 2) //request i2c on gpio 0 and gpio2 as i have 8 pin esp. In this case, i have no pin left for setting RTS from esp.
Is it still ok if i do not send RTS and Reset from esp?

If possible can you plz just map the esp8266 and arduino mapping considering 8 pin?

- Tue Jan 31, 2017 1:11 pm #61827 I tried flashing code to esp8266 using wire.begin(0,1), it does not work because while in flashmode, GPIO_0 of esp needs to be connected to GND. Any suggestions ?

- Tue Jan 31, 2017 5:52 pm #61841 Since GPIO2/GPIO0 needs PullUp for normal boot in execution mode, there is no issue using them for I2C since I2C also requires those PullUps. Grounding GPIO0 for sketch upload isn't not an issue either, because I2C is idle during that moment.

- Tue Jan 31, 2017 6:52 pm #61843 I was trying to use gpio0 and gpio2 of esp8266 to be used for ESP as master.

Do you mean following piece of code should work that was uploaded to ESP8266 as I2C master ??
-------- "wire.begin (0, 2)" //GPIO_0 and GPIO_2.

But as I know, GPIO_0 should be connected to GND while uploading the code that will run on ESP, how will this work ??