PyArduinoFlash is an open source library in Python for updating the firmware of Arduino boards that use the ATmegaBOOT_168 or Arduino Stk500V2 bootloader, for example Arduino Nano or Arduino Uno or Arduino Mega 2560 and many more.
The intention is to have a class that can be imported into any python project to update the Arduinos through the serial port.
It implements a subset of Atmel's STK-500V1 and STK500V2 protocol, using as reference the protocols implemented by Avrdude in the arduino.c and wiring.c modules.
For Arduino's using Atmel AVR8 processors there are three versions of the bootoloader available. For boards that have less than 128 Kbytes of Flash memory, for example Nano or Uno using the Atmega328P, etc that are marked in the Arduino IDE as older you have to use STK500-V1 at 57600 baud. And for the new ones (they implement the Optiboot bootloader) you have to use STK500-V1 at 115200 baud. For boards that have processors of more than 128 Kbytes, for example the Mega 2560, the STK500-V2 protocol must be used at 115200 baud.
As an example of use, there is an APP in KivyMd and Kivy that exposes through a GUI all the methods required to update and verify the firmware.
The first example shows the upgrade of a Nano board with a new bootolader. Select STK500-V1 at 115200 baud.
The second example shows the upgrade of a Mega board with 2560 processor. STK500-V2 must be selected at 115200 baud.
Install using pip or pip3 (recommended, no separate download required):
pip install arduinobootloader
from intelhex import IntelHex
from arduinobootloader import ArduinoBootloader
def update(self):
ih = IntelHex()
ab = ArduinoBootloader()
prg = ab.select_programmer("Stk500v1")
if prg.open(speed=115200):
if not prg.board_request():
prg.close()
return
print("botloader name: {} version: {} hardware: {}".format(ab.programmer_name,
ab.sw_version,
ab.hw_version))
if not prg.cpu_signature():
prg.close()
return
print("cpu name: {}".format(ab.cpu_name) )
try:
ih.fromfile("filename.hex", format='hex')
except (FileNotFoundError, AddressOverlapError, HexRecordError):
return
for address in range(0, ih.maxaddr(), ab.cpu_page_size):
buffer = ih.tobinarray(start=address, size=ab.cpu_page_size)
if not prg.write_memory(buffer, address):
print("Write error")
prg.leave_bootloader()
prg.close()
return
for address in range(0, ih.maxaddr(), ab.cpu_page_size):
buffer = ih.tobinarray(start=address, size=ab.cpu_page_size)
read_buffer = prg.read_memory(address, ab.cpu_page_size)
if read_buffer is None:
print("Read error")
break
if buffer != read_buffer:
print("File not match")
break
prg.leave_bootloader()
prg.close()The parsing of the file in Intel hexadecimal format is done with the IntelHex library.
To have an instance of the class use ab = ArduinoBootloader()
Then select the protocol of the programmer prg = ab.select_protocol("Stk500v1") . To establish the connection with the bootloader of the Arduino board use prg.open() that returns True when it is successful.
As the library needs the information of the CPU to know the size and count of the flash page, use the method prg.board_request() and prg.cpu_signature()
If the previous was successfully (they return True), now open the hexadecimal file with the ih.fromfile("firmware_file.hex", format='hex') function. If there are errors in the format or the file path is invalid, exceptions are thrown.
To obtain the page of the current address, use the ih.tobinarray(start=address, size=ab.cpu_page_size) .
For write it in the flash memory, use the method prg.write_memory(buffer, address) which take the buffer and the address as parameters. Returns True when success.
The read to verify is done in the same way, with the exception that the method returns the read buffer. If it is None it indicates that there were problems.
The bootloader begins the execution of the firmware after a period of time without receiving communication; nevertheless it is convenient to execute the function prg.leave_bootloader().
Call the method prg.close() to release the serial port.
The Script folder contains arduinoflash.py file that allows update or read the firmware of Arduino boards.
One of the purposes is to show the use of the PyArduinoBootloader library in conjunction with the IntelHex library to process hexadecimal files.
Use the argparse library, to read the command line (file and options).
And to indicate the progress the progressbar2 library.
usage: arduinoflash.py [-h] [--version] [-r | -u] filename
arduino flash utility
positional arguments:
filename filename in hexadecimal Intel format
optional arguments:
-h, --help show this help message and exit
--version script version
-b BAUDRATE, --baudrate BAUDRATE
old bootolader (57600) Optiboot (115200)
-p PROGRAMMER, --programmer PROGRAMMER
programmer version - Nano (Stk500v1) Mega (Stk500v2)
-r, --read read the cpu flash memory
-u, --update update cpu flash memory
The following capture shows the reading of the flash memory of an Arduino Nano board.
And the next shows the firmware update of an Arduino Nano board.
The following capture shows the reading of the flash memory of an Arduino Mega 2560 board.
And the next shows the firmware update of an Arduino Mega 2560 board.
If you need assistance, contact me:
- Email : juanschiavoni@gmail.com
- PyArduinoFlash is released under the terms of the MIT License. Please refer to the LICENSE file.