Display esp8266 notes in README.md

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README.md

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-Arduino
+Arduino IDE with ESP8266 support
-========
+================================
 
-* Arduino is an open-source physical computing platform based on a simple i/o
+This is an early beta. Things might not work as expected, please do report any bugs you find.
-board and a development environment that implements the Processing/Wiring
-language. Arduino can be used to develop stand-alone interactive objects or
-can be connected to software on your computer (e.g. Flash, Processing, MaxMSP).
-The boards can be assembled by hand or purchased preassembled; the open-source
-IDE can be downloaded for free at http://arduino.cc/en/Main/Software
 
-* For more information, see the website at: http://www.arduino.cc/
+What works
-or the forums at: http://arduino.cc/forum/  
+----------
-You can also follow Arduino on twitter at: https://twitter.com/arduino or like Arduino on Facebook at: https://www.facebook.com/official.arduino
 
-* To report a *bug* in the software or to request *a simple enhancement* go to:
+- **pinMode, digitalRead, digitalWrite**
-http://github.com/arduino/Arduino/issues
 
-* More complex requests and technical discussion should go on the Arduino Developers
+	Pin numbers correspond directly to the esp8266 GPIO pin numbers. To read GPIO2,
-mailing list:
+	call digitalRead(2);
-https://groups.google.com/a/arduino.cc/forum/#!forum/developers
+	GPIO0-GPIO15 can be INPUT, OUTPUT, INPUT_PULLUP, and OUTPUT_OPEN_DRAIN.
+	GPIO16 can be INPUT or OUTPUT.
 
-* If you're interested in modifying or extending the Arduino software, we strongly 
+- **analogRead(0)** reads the value of the ADC channel connected to the TOUT pin.
-suggest discussing your ideas on the Developers mailing list *before* starting
-to work on them. That way you can coordinate with the Arduino Team and others,
-giving your work a higher chance of being integrated into the official release
-https://groups.google.com/a/arduino.cc/forum/#!forum/developers
 
-Installation
+- **pin interrupts (attachInterrupt, detachInterrupt)**
-------------
-Detailed instructions are in reference/Guide_Windows.html and
-reference/Guide_MacOSX.html.  For Linux, see the Arduino playground:
-http://www.arduino.cc/playground/Learning/Linux
 
-Credits
+	Interrupts may be attached to any GPIO pin, except GPIO16. Standard Arduino interrupt 
---------
+	types are supported: CHANGE, RISING, FALLING.
-Arduino is an open source project, supported by many.
 
-The Arduino team is composed of Massimo Banzi, David Cuartielles, Tom Igoe,
+- **shiftIn, shiftOut**
-Gianluca Martino, Daniela Antonietti, and David A. Mellis.
+- **millis, micros**
+- **delay, delayMicroseconds, yield**
 
-Arduino uses the [GNU avr-gcc toolchain](http://gcc.gnu.org/wiki/avr-gcc), [avrdude](http://www.nongnu.org/avrdude/), [avr-libc](http://www.nongnu.org/avr-libc/), and code from
+	Remember that there is a lot of code that needs to run on the chip besides the sketch 
-[Processing](http://www.processing.org) and [Wiring](http://wiring.org.co).
+	when WiFi is connected. WiFi and TCP/IP libraries get a chance to handle any pending
+	events each time the loop() function completes, OR when delay(...) is called.
+	If you have a loop somewhere in your sketch that takes a lot of time (>50ms) without
+	calling delay(), you might consider adding a call to delay function to keep the WiFi
+	stack running smoothly.
+	There is also a yield() function which is equivalent to delay(0). The delayMicroseconds
+	function, on the other hand, does not yield to other tasks, so using it for delays
+	more than 20 milliseconds is not recommended.
+
+- **Serial**
+
+	Only 8n1 is supported right now. By default the diagnostic output from WiFi 
+	libraries is disabled when you call Serial.begin. To enable debug output again,
+	call Serial.setDebugOutput(true);
+
+- **Ticker**
+
+	Library for calling functions repeatedly with a certain period. Two examples included.
+
+- **EEPROM**
+
+	This is a bit different from standard EEPROM class. You need to call EEPROM.begin(size)
+	before you start reading or writing, size being the number of bytes you want to use.
+	Size can be anywhere between 4 and 4096 bytes.
+	EEPROM.write does not write to flash immediately, instead you must call EEPROM.commit()
+	whenever you wish to save changes to flash. EEPROM.end() will also commit, and will
+	release the RAM copy of EEPROM contents. 
+	Three examples included.
+
+- **I2C (Wire library)**
+
+	Only master mode works, and I haven't tested if Wire.setClock gives correct frequency.
+	Before using I2C, you need to set pins you will use for SDA and SCL by calling
+	Wire.pins(int sda, int scl), i.e. Wire.pins(0, 2); on ESP-01.
+
+- **OneWire (from https://www.pjrc.com/teensy/td_libs_OneWire.html)**
+
+	Library was adapted to work with ESP8266 by including register definitions into OneWire.h
+	Note that if you have OneWire library in your Arduino/libraries folder, it will be used
+	instead of the one that comes with the Arduino IDE (this one).
+
+- **WiFi(ESP8266WiFi library)**
+
+	This is mostly similar to WiFi shield library. Differences include:
+		* WiFi.mode(m): set mode to WIFI_AP, WIFI_STA, or WIFI_AP_STA.
+		* call WiFi.softAP(ssid) to set up an open network
+		* call WiFi.softAP(ssid, passphrase) to set up a WPA2-PSK network
+		* WiFi.macAddress(mac) is for STA, WiFi.softAPmacAddress(mac) is for AP.
+		* WiFi.localIP() is for STA, WiFi.softAPIP() is for AP.
+		* WiFi.RSSI() doesn't work
+		* WiFi.printDiag(Serial); will print out some diagnostic info
+	WiFiServer, WiFiClient, and WiFiUDP behave mostly the same way as with WiFi shield library.
+	Three samples are provided for this library.
+
+- **mDNS responder (ESP8266mDNS library)**
+
+	Allows the sketch to respond to multicast DNS queries for domain names like "foo.local".
+	See attached example and library README file for details.
+
+- Other libraries that don't rely on low-level access to AVR registers.
+
+- Upload via serial port
+	Select "esptool" as a programmer, and pick the correct serial port.
+	You need to put ESP8266 into bootloader mode before uploading code (pull GPIO0 low and 
+	toggle power).
+
+What is not done yet
+--------------------
+
+- analogWrite (PWM). ESP8266 has only one hardware PWM source. It is not yet clear how to use it with analogWrite API. Software PWM is also an option, but apparently it causes issues with WiFi connectivity.
+- pulseIn
+- SPI. HSPI and bit-banging are two interfaces that will be supported.
+- I2C slave mode
+- Serial modes other than 8n1
+- WiFi.RSSI. SDK doesn't seem to have an API to get RSSI for the current network. So far the only
+	way to obtain RSSI is to disconnect, perform a scan, and get the RSSI value from there.
+- Upload sketches via WiFi. Conceptually and technically simple, but need to figure out how to provide the best UX for this feature.
+- Samples for all the libraries
+
+
+License and credits
+-------------------
+
+Arduino IDE is licensed under GPL, with Arduino core libraries licensed under LGPL.
+
+This build includes an xtensa gcc toolchain, which is also under GPL.
+
+Espressif SDK included in this build is under Espressif Public License.
+
+Esptool written by Christian Klippel is licensed under GPLv2. 
+The source with my modfications is available on github: https://github.com/igrr/esptool-ck
+
+ESP8266 port contributed by Ivan Grokhotkov, ivan@esp8266.com.
 
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