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Diffstat (limited to 'docs/wipy')
| -rw-r--r-- | docs/wipy/general.rst | 32 |
1 files changed, 26 insertions, 6 deletions
diff --git a/docs/wipy/general.rst b/docs/wipy/general.rst index 67f47f21e..976fb6891 100644 --- a/docs/wipy/general.rst +++ b/docs/wipy/general.rst @@ -32,15 +32,35 @@ Boot modes ---------- If you power up normally, or press the reset button, the WiPy will boot -into standard mode: the ``boot.py`` file will be executed first, then +into standard mode; the ``boot.py`` file will be executed first, then ``main.py`` will run. You can override this boot sequence by pulling ``GPIO28`` **up** (connect -it to the 3v3 output pin) during reset. The heart beat LED will flash slowly -3 times to signal that safe boot is being requested, and then 4 more times -quickly to let you know that safe boot is going to be performed. While safe -booting, the WiPy runs the factory firmware and skips the execution of -``boot.py`` and ``main.py``. This is useful to recover from any crash situation. +it to the 3v3 output pin) during reset. This procedure also allows going +back in time to old firmware versions. The WiPy can hold up to 3 different +firmware versions, which are: the factory firmware plus 2 user updates. + +After reset, if ``GPIO28`` is held high, the heart beat LED will start flashing +slowly, if after 3 seconds the pin is still being held high, the LED will start +blinking a bit faster and the WiPy will select the previous user update to boot. +If the previous user update is the desired firmware image, ``GPIO28`` must be +released before 3 more seconds elapse. If 3 seconds later the pin is still high, +the factory firmware will be selected, the LED will flash quickly for 1.5 seconds +and the WiPy will proceed to boot. The firmware selection mechanism is as follows: + + +**Safe Boot Pin** ``GPIO28`` **released during:** + ++-------------------------+-------------------------+----------------------------+ +| 1st 3 secs window | 2nd 3 secs window | Final 1.5 secs window | ++=========================+=========================+============================+ +| | Normal boot, *latest* | | Safe boot, *previous* | | Safe boot, the *factory* | +| | firmware is selected | | user update selected | | firmware is selected | ++-------------------------+-------------------------+----------------------------+ + +When selecting a previous firmware version, safe boot mode is entered, meaning +that the execution of both ``boot.py`` and ``main.py`` is skipped. This is +useful to recover from crash situations caused by the user scripts. The heart beat LED ------------------ |