Safe Boot - Pycom WiPy 3.0 Manual

1.3.6 Safe boot
Boot Modes
If powering up normally or upon pressing the reset button, a Pycom module will boot into
standard mode; the
boot.py
alter the boot procedure of the module by tying certain pins
boots.
Bootloader
If you updated your device before using it, you have already put the device into bootloader
mode. This is achieved by connecting
Pysense/Pytrack to update, it did this automatically for you. You only need to put your
Pycom module into bootloader mode if you are updating its firmware, or are programming
your own low level code. This is not required if you are updating your MicroPython code.
Safe Boot
Some times the code you have written will prevent you gaining access to the REPL or
prevent you updating your code. Some example may be:
You disabled the WiFi/UART
Your code gets stuck before reaching the REPL
You set a socket as blocking but never receive any data
In order to fix this you can safe boot your module. This will prevent
from being executed and will drop you straight into the interactive REPL. After reset, if
pin is held (i.e. connect it to the
high
flashing orange slowly. If after 3 seconds the pin is still held high, the LED will start blinking
faster. In this mode the module will do the same as previously explained but it will also select
the previous OTA image to boot if you have updated the module via the OTA update
procedure (updates performed via the firmware update tool do not count). This is useful if
you flashed a OTA update that breaks the device.
Pin released during:
P12
1st 3 secs window
Disable and
boot.py
The selection made during safe boot is not persistent, therefore after the next normal reset,
the latest firmware will proceed to run again.
file will be executed first, followed by
to
G23
output pin), the heartbeat LED will begin
3V3
same as previous but using previous OTA firmware
main.py
main.py
or
high
while the device boots. If you used a
GND
boot.py
2nd 3 secs window
. It is possible to
when the module
low
and
main.py
P12
85