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Introduction to MicroPython on the ESP8266
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==========================================
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Using MicroPython is a great way to get the most of your ESP8266 board. And
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vice versa, the ESP8266 chip is a great platform for using MicroPython. This
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tutorial will guide you through setting up MicroPython, getting a prompt, using
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WebREPL, connecting to the network and communicating with the Internet, using
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the hardware peripherals, and controlling some external components.
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Let's get started!
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Requirements
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------------
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The first thing you need is a board with an ESP8266 chip. The MicroPython
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software supports the ESP8266 chip itself and any board should work. The main
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characteristic of a board is how much flash it has, how the GPIO pins are
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connected to the outside world, and whether it includes a built-in USB-serial
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convertor to make the UART available to your PC.
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The minimum requirement for flash size is 512k. A board with this amount of
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flash will not have room for a filesystem, but otherwise is fully functional.
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If your board has 1Mbyte or more of flash then it will support a filesystem.
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Names of pins will be given in this tutorial using the chip names (eg GPIO0)
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and it should be straightforward to find which pin this corresponds to on your
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particular board.
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Powering the board
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------------------
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If your board has a USB connector on it then most likely it is powered through
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this when connected to your PC. Otherwise you will need to power it directly.
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Please refer to the documentation for your board for further details.
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Deploying the firmware
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----------------------
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The very first thing you need to do is put the MicroPython firmware (compiled
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code) on your ESP8266 device. There are two main steps to do this: first you
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need to put your device in boot-loader mode, and second you need to copy across
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the firmware. The exact procedure for these steps is highly dependent on the
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particular board and you will need to refer to its documentation for details.
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If you have a board that has a USB connector, a USB-serial convertor, and has
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the DTR and RTS pins wired in a special way then deploying the firmware should
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be easy as all steps can be done automatically. Boards that have such features
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include the Adafruit Feather HUZZAH and NodeMCU boards.
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For best results it is recommended to first erase the entire flash of your
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device before putting on new MicroPython firmware.
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Currently we only support esptool.py to copy across the firmware. You can find
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this tool here: `<https://github.com/themadinventor/esptool/>`__, or install it
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using pip::
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pip install esptool
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It requires Python 2.7, so you may need to use ``pip2`` instead of ``pip`` in
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the command above. Any other
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flashing program should work, so feel free to try them out, or refer to the
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documentation for your board to see its recommendations.
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Using esptool.py you can erase the flash with the command::
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esptool.py --port /dev/ttyUSB0 erase_flash
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And then deploy the new firmware using::
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esptool.py --port /dev/ttyUSB0 --baud 460800 write_flash --flash_size=8m 0 esp8266-2016-05-03-v1.8.bin
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You might need to change the "port" setting to something else relevant for your
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PC. You may also need to reduce the baudrate if you get errors when flashing
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(eg down to 115200). The filename of the firmware should also match the file
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that you have.
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If you have a NodeMCU board, you may need to use the following command to deploy
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the firmware (note the "-fm dio" option)::
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esptool.py --port /dev/ttyUSB0 --baud 460800 write_flash --flash_size=8m -fm dio 0 esp8266-2016-05-03-v1.8.bin
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If the above commands run without error then MicroPython should be installed on
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your board!
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Serial prompt
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-------------
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Once you have the firmware on the device you can access the REPL (Python prompt)
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over UART0 (GPIO1=TX, GPIO3=RX), which might be connected to a USB-serial
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convertor, depending on your board. The baudrate is 115200. The next part of
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the tutorial will discuss the prompt in more detail.
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WiFi
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----
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After a fresh install and boot the device configures itself as a WiFi access
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point (AP) that you can connect to. The ESSID is of the form MicroPython-xxxxxx
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where the x's are replaced with part of the MAC address of your device (so will
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be the same everytime, and most likely different for all ESP8266 chips). The
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password for the WiFi is micropythoN (note the upper-case N). Its IP address
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will be 192.168.4.1 once you connect to its network. WiFi configuration will
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be discussed in more detail later in the tutorial.
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