Commit a9923d19 authored by Paul Sokolovsky's avatar Paul Sokolovsky
Browse files

docs/esp8266/intro: Add troubleshooting section.

Tries to summarize most of the issues we've seen so far.
parent 919c54f7
......@@ -101,3 +101,61 @@ be the same everytime, 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, as by the common safety standards they are considered
a hazard which may lead to electrical device breakdown and eletric shock to
humans. Please avoid using unearthed power connections at any time. In regard
to FlashROM hardware problems, there are independent (not related to MicroPython
in any way) reports
`(e.g.) <https://github.com/peterhinch/micropython-samples.git>`_
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 convertor, 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.
* 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/themadinventor/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.
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