You are using the wrong SDK
Look here: https://github.com/espressif/esp-idf

first open Terminal.app
then: then open/restart Arduino IDE

There was a problem with SerialRX because we switched to APP CPU for the loop thread, but I should have it fixed in a commit a few hours ago. Please pull the latest changes and try again

@MarsWarrior default I2C pins are defined only in software. There are no default pins for I2C actually and they are all attached through the pin matrix. Me and Ivan have decided to use those particular ones as they are attached to the gpio power and do not have any other major Arduino uses (like ADC...

@a2retro You can attach all 3 UARTs to any pins you like (almost). Pins 9 and 10 are tied to your flash chip, so I would not use them for Serial. You can check esp32-hal-uart.h if you want C style api to the serial or just use HardwareSerial Serial1(1); and then Serial1.begin(baudrate, SERIAL_8N1, r...

Hey Neil :) Says 1.6.9 because that is the last version I have here and did not put much thought into it yet. Will test newer versions and will update the tools we have for arduino to cover the new stuff as well. Currently get.py only downloads the toolchain and nothing more. Will do more things in ...

Hello everyone! I'm glad to announce to you that an initial Arduino environment for the ESP32 has been uploaded HERE . Not everything is working yet, you can not get it through package manager, but you can give it a go and help us find bugs :) The framework can also be downloaded as component in an ...

Aye. Just for clarity: I wasn't trying to sweep the excellent work you did under the rug; just saying that Espressif actually is aware of the Arduino environment and we're taking active steps to help on that environment, although they may not be outwardly visible at this moment. We need to get the ...

There already is Arduino support. At least for the things that have been disclosed so far. Support will be added as Espressif releases anything new (last update was committed on Dec 18, 2015).
https://github.com/me-no-dev/ESP31B

Check LWIP headers. All network functionality is there (apart from udp multicast).
There is no espconn_* but espconn is an abstraction of the lwip provided functions anyway.