Boot Modes
If powering up normally or upon pressing the reset button, a Pycom module will
boot into standard mode; the boot.py file will be executed first,
followed by main.py. It is possible to alter the boot procedure of the
module by tying certain pins high or low when the module boots.
Bootloader
If you updated your device before using it, you have already put the device into
bootloader mode. This is achieved by connecting G23 to GND while the device
boots. If you used a 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 boot.py
and main.py from being executed and will drop you straight into the interactive
REPL. After reset, if P12 pin is held high (i.e. connect it to the 3V3
output pin), the heartbeat LED will begin 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 P12 released during:
| 1st 3 secs window | 2nd 3 secs window |
|---|---|
Disable boot.py and main.py |
same as previous but using previous OTA firmware |
The selection made during safe boot is not persistent, therefore after the next normal reset, the latest firmware will proceed to run again.
If problems occur within the filesystem or you wish to factory reset your module to remove your code, run following code in the REPL:
>>> import os
>>> os.mkfs('/flash')
Be aware, resetting the flash filesystem will delete all files inside the internal device storage (not the SD card) and they cannot be recovered.
Reset
Pycom devices support both soft and hard resets. A soft reset clears the state
of the MicroPython virtual machine but leaves hardware peripherals unaffected.
To do a soft reset, press Ctrl+D on the REPL or from within a script, run:
>>> import sys
>>> sys.exit()
A hard reset is the same as performing a power cycle to the device. In order to
hard reset the device, press the reset switch or run:
>>> import machine
>>> machine.reset()