kopia lustrzana https://github.com/micropython/micropython
213 wiersze
9.7 KiB
ReStructuredText
213 wiersze
9.7 KiB
ReStructuredText
.. _intro:
|
|
|
|
Getting started with MicroPython on the ESP8266
|
|
===============================================
|
|
|
|
Using MicroPython is a great way to get the most of your ESP8266 board. And
|
|
vice versa, the ESP8266 chip is a great platform for using MicroPython. This
|
|
tutorial will guide you through setting up MicroPython, getting a prompt, using
|
|
WebREPL, connecting to the network and communicating with the Internet, using
|
|
the hardware peripherals, and controlling some external components.
|
|
|
|
Let's get started!
|
|
|
|
Requirements
|
|
------------
|
|
|
|
The first thing you need is a board with an ESP8266 chip. The MicroPython
|
|
software supports the ESP8266 chip itself and any board should work. The main
|
|
characteristic of a board is how much flash it has, how the GPIO pins are
|
|
connected to the outside world, and whether it includes a built-in USB-serial
|
|
converter to make the UART available to your PC.
|
|
|
|
The minimum requirement for flash size is 1Mbyte. There is also a special
|
|
build for boards with 512KB, but it is highly limited comparing to the
|
|
normal build: there is no support for filesystem, and thus features which
|
|
depend on it won't work (WebREPL, mip, etc.). As such, 512KB build will
|
|
be more interesting for users who build from source and fine-tune parameters
|
|
for their particular application.
|
|
|
|
Names of pins will be given in this tutorial using the chip names (eg GPIO0)
|
|
and it should be straightforward to find which pin this corresponds to on your
|
|
particular board.
|
|
|
|
Powering the board
|
|
------------------
|
|
|
|
If your board has a USB connector on it then most likely it is powered through
|
|
this when connected to your PC. Otherwise you will need to power it directly.
|
|
Please refer to the documentation for your board for further details.
|
|
|
|
Getting the firmware
|
|
--------------------
|
|
|
|
The first thing you need to do is download the most recent MicroPython firmware
|
|
.bin file to load onto your ESP8266 device. You can download it from the
|
|
`MicroPython downloads page <http://micropython.org/download#esp8266>`_.
|
|
From here, you have 3 main choices
|
|
|
|
* Stable firmware builds for 1024kb modules and above.
|
|
* Daily firmware builds for 1024kb modules and above.
|
|
* Daily firmware builds for 512kb modules.
|
|
|
|
If you are just starting with MicroPython, the best bet is to go for the Stable
|
|
firmware builds. If you are an advanced, experienced MicroPython ESP8266 user
|
|
who would like to follow development closely and help with testing new
|
|
features, there are daily builds (note: you actually may need some
|
|
development experience, e.g. being ready to follow git history to know
|
|
what new changes and features were introduced).
|
|
|
|
Support for 512kb modules is provided on a feature preview basis. For end
|
|
users, it's recommended to use modules with flash of 1024kb or more. As
|
|
such, only daily builds for 512kb modules are provided.
|
|
|
|
Deploying the firmware
|
|
----------------------
|
|
|
|
Once you have the MicroPython firmware (compiled code), you need to load it onto
|
|
your ESP8266 device. There are two main steps to do this: first you
|
|
need to put your device in boot-loader mode, and second you need to copy across
|
|
the firmware. The exact procedure for these steps is highly dependent on the
|
|
particular board and you will need to refer to its documentation for details.
|
|
|
|
If you have a board that has a USB connector, a USB-serial converter, and has
|
|
the DTR and RTS pins wired in a special way then deploying the firmware should
|
|
be easy as all steps can be done automatically. Boards that have such features
|
|
include the Adafruit Feather HUZZAH and NodeMCU boards.
|
|
|
|
If you do not have such a board, you need keep GPIO0 pulled to ground and reset
|
|
the device by pulling the reset pin to ground and releasing it again to enter
|
|
programming mode.
|
|
|
|
For best results it is recommended to first erase the entire flash of your
|
|
device before putting on new MicroPython firmware.
|
|
|
|
Currently we only support esptool.py to copy across the firmware. You can find
|
|
this tool here: `<https://github.com/espressif/esptool/>`__, or install it
|
|
using pip::
|
|
|
|
pip install esptool
|
|
|
|
Versions starting with 1.3 support both Python 2.7 and Python 3.4 (or newer).
|
|
An older version (at least 1.2.1 is needed) works fine but will require Python
|
|
2.7.
|
|
|
|
Any other flashing program should work, so feel free to try them out or refer
|
|
to the documentation for your board to see its recommendations.
|
|
|
|
Using esptool.py you can erase the flash with the command::
|
|
|
|
esptool.py --port /dev/ttyUSB0 erase_flash
|
|
|
|
And then deploy the new firmware using::
|
|
|
|
esptool.py --port /dev/ttyUSB0 --baud 460800 write_flash --flash_size=detect 0 esp8266-20170108-v1.8.7.bin
|
|
|
|
You might need to change the "port" setting to something else relevant for your
|
|
PC. You may also need to reduce the baudrate if you get errors when flashing
|
|
(eg down to 115200). The filename of the firmware should also match the file
|
|
that you have.
|
|
|
|
For some boards with a particular FlashROM configuration (e.g. some variants of
|
|
a NodeMCU board) you may need to manually set a compatible
|
|
`SPI Flash Mode <https://github.com/espressif/esptool/wiki/SPI-Flash-Modes>`_.
|
|
You'd usually pick the fastest option that is compatible with your device, but
|
|
the ``-fm dout`` option (the slowest option) should have the best compatibility::
|
|
|
|
esptool.py --port /dev/ttyUSB0 --baud 460800 write_flash --flash_size=detect -fm dout 0 esp8266-20170108-v1.8.7.bin
|
|
|
|
If the above commands run without error then MicroPython should be installed on
|
|
your board!
|
|
|
|
If you pulled GPIO0 manually to ground to enter programming mode, release it
|
|
now and reset the device by again pulling the reset pin to ground for a short
|
|
duration.
|
|
|
|
Serial prompt
|
|
-------------
|
|
|
|
Once you have the firmware on the device you can access the REPL (Python prompt)
|
|
over UART0 (GPIO1=TX, GPIO3=RX), which might be connected to a USB-serial
|
|
converter, depending on your board. The baudrate is 115200. The next part of
|
|
the tutorial will discuss the prompt in more detail.
|
|
|
|
WiFi
|
|
----
|
|
|
|
After a fresh install and boot the device configures itself as a WiFi access
|
|
point (AP) that you can connect to. The ESSID is of the form MicroPython-xxxxxx
|
|
where the x's are replaced with part of the MAC address of your device (so will
|
|
be the same every time, and most likely different for all ESP8266 chips). The
|
|
password for the WiFi is micropythoN (note the upper-case N). Its IP address
|
|
will be 192.168.4.1 once you connect to its network. WiFi configuration will
|
|
be discussed in more detail later in the tutorial.
|
|
|
|
Troubleshooting installation problems
|
|
-------------------------------------
|
|
|
|
If you experience problems during flashing or with running firmware immediately
|
|
after it, here are troubleshooting recommendations:
|
|
|
|
* Be aware of and try to exclude hardware problems. There are 2 common problems:
|
|
bad power source quality and worn-out/defective FlashROM. Speaking of power
|
|
source, not just raw amperage is important, but also low ripple and noise/EMI
|
|
in general. If you experience issues with self-made or wall-wart style power
|
|
supply, try USB power from a computer. Unearthed power supplies are also known
|
|
to cause problems as they source of increased EMI (electromagnetic interference)
|
|
- at the very least, and may lead to electrical devices breakdown. So, you are
|
|
advised to avoid using unearthed power connections when working with ESP8266
|
|
and other boards. In regard to FlashROM hardware problems, there are independent
|
|
(not related to MicroPython in any way) reports
|
|
`(e.g.) <http://internetofhomethings.com/homethings/?p=538>`_
|
|
that on some ESP8266 modules, FlashROM can be programmed as little as 20 times
|
|
before programming errors occur. This is *much* less than 100,000 programming
|
|
cycles cited for FlashROM chips of a type used with ESP8266 by reputable
|
|
vendors, which points to either production rejects, or second-hand worn-out
|
|
flash chips to be used on some (apparently cheap) modules/boards. You may want
|
|
to use your best judgement about source, price, documentation, warranty,
|
|
post-sales support for the modules/boards you purchase.
|
|
|
|
* The flashing instructions above use flashing speed of 460800 baud, which is
|
|
good compromise between speed and stability. However, depending on your
|
|
module/board, USB-UART converter, cables, host OS, etc., the above baud
|
|
rate may be too high and lead to errors. Try a more common 115200 baud
|
|
rate instead in such cases.
|
|
|
|
* If lower baud rate didn't help, you may want to try older version of
|
|
esptool.py, which had a different programming algorithm::
|
|
|
|
pip install esptool==1.0.1
|
|
|
|
This version doesn't support ``--flash_size=detect`` option, so you will
|
|
need to specify FlashROM size explicitly (in megabits). It also requires
|
|
Python 2.7, so you may need to use ``pip2`` instead of ``pip`` in the
|
|
command above.
|
|
|
|
* The ``--flash_size`` option in the commands above is mandatory. Omitting
|
|
it will lead to a corrupted firmware.
|
|
|
|
* To catch incorrect flash content (e.g. from a defective sector on a chip),
|
|
add ``--verify`` switch to the commands above.
|
|
|
|
* Additionally, you can check the firmware integrity from a MicroPython REPL
|
|
prompt (assuming you were able to flash it and ``--verify`` option doesn't
|
|
report errors)::
|
|
|
|
import esp
|
|
esp.check_fw()
|
|
|
|
If the last output value is True, the firmware is OK. Otherwise, it's
|
|
corrupted and need to be reflashed correctly.
|
|
|
|
* If you experience any issues with another flashing application (not
|
|
esptool.py), try esptool.py, it is a generally accepted flashing
|
|
application in the ESP8266 community.
|
|
|
|
* If you still experience problems with even flashing the firmware, please
|
|
refer to esptool.py project page, https://github.com/espressif/esptool
|
|
for additional documentation and bug tracker where you can report problems.
|
|
|
|
* If you are able to flash firmware, but ``--verify`` option or
|
|
``esp.check_fw()`` return errors even after multiple retries, you
|
|
may have a defective FlashROM chip, as explained above.
|