If there's no port_config.py file, or it lacks WEBREPL_PASS variable,
"initial setup mode" will be entered on first WebREPLconnection. User
will be asked for password, which will be written to
port_config.WEBREPL_PASS, and system restarted to work in normal mode
with password active.
Changes are:
- added OneWireError exception and used where errors can occur
- renamed read/write functions to use same names as C _onewire funcs
- read_bytes is now read, write_bytes is now write
- add ability to read/write DS18B20 scratch pad
- rename start_measure to convert_temp (since that's what it does)
- rename get_temp to read_temp (consistency with other read names)
- removed test function
All Flash sans firmware at the beginning and 16K SDK param block at the
end is used for filesystem (and that's calculated depending on the Flash
size).
Flash size as seen by vendor SDK doesn't depend on real size, but rather on
a particular value in firmware header, as put there by flash tool. That means
it's user responsibility to know what flash size a particular device has, and
specify correct parameters during flashing. That's not end user friendly
however, so we try to make it "flash and play" by detecting real size vs
from-header size mismatch, and correct the header accordingly.
"" is the correct name of the root directory when mounting a device there
(as opposed to "/"). One can now do os.listdir('/') and open('/abc'), as
well as os.listdir() and open('abc').
Main entry point is _boot.py which checks whether FAT FS in flash mountable,
and if so, mounts it. Otherwise, it checks if flash is empty, and if so,
performs initial module setup: makes FAT FS, configures default AP name,
etc. As a last option, if flash is not empty, and could not be mounted,
it means filesystem corruption, and warning message with instructions is
printed in an infinite loop.
