Usage¶
The following paragraph explains the basic flow to update the firmware of an Arduino board from Python.
Requirements¶
If the firmware file is in Intel hexadecimal format, use the IntelHex library.
Select Programmer¶
Get a instance of the class with
ab = ArduinoBootloader()
and select the protocol of the programmer with
prg = ab.select_protocol("Stk500v1")
Connect¶
To establish the connection with the Arduino bootloader use
if prg.open(speed=115200):
that returns True when successful.
CPU information¶
The library needs the information of the CPU to know the size and count of the flash page, use the method
if prg.cpu_signature():
that returns True when success. The properties have the corresponding information
ab.cpu_page_size
ab.cpu_pages
Programmer information¶
Although the information of the programmer is not important for the update process, because the bootoloader is an emulation of the Atmel programmers, you can do it with the method
prg.board_request()
that returns True when success.
The properties have the information.
ab.programmer_name
ab.sw_version
ab.hw_version
Open Firmware File¶
Open the hexadecimal file with the method. If there are errors in the format or the file path is invalid, exceptions are thrown.
try:
ih.fromfile("filename.hex", format='hex')
except FileNotFoundError:
print("file not found")
except (AddressOverlapError, HexRecordError):
print("error, file format")
Parse the Firmware in Pages¶
To obtain the page of the current address, use the
buffer = ih.tobinarray(start=address, size=ab.cpu_page_size)
Write Pages¶
For write it in the flash memory, use this method which take the buffer and the address as parameters and returns True when success.
if prg.write_memory(buffer, address):
Read Pages¶
The read for example to verify, is done in the same way, with the exception that the method returns the memory buffer. When errors returns None.
read_buffer = prg.read_memory(address, ab.cpu_page_size)
if read_buffer is None:
Save in a File¶
To save the read firmware to a hexadecimal format file, you need to buffer it in a dictionary where the key is the address of each byte on the page.
for i in range(0, ab.cpu_page_size):
dict_hex[address + i] = read_buffer[i]
And when you have finished reading the flash, add the starting address to generate the hexadecimal and to save the file
dict_hex["start_addr"] = 0
ih.fromdict(dict_hex)
ih.tofile("read_filename.hex", 'hex')
Execute the Firmware¶
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()