Only write if byte is different

[b-blake]

Only Write to a byte if it is different. Read the byte and compare before writing the byte.

[FoamyGuy]

I do like this idea. It seems like it should save a little bit of wear on the device by not writing unless necessary.

Are you interested in submitting a PR with this change perhaps?

[b-blake]

What is a PR? How do I submit one? Do I get and Brownie Points?

It will have the biggest impact when erasing an EEPROM.

[FoamyGuy]

@b-blake PR is Pull Request. Essentially it's proposing a change in the library that then can get reviewed by project maintainers and merged in if accepted.

There is a guide here: https://learn.adafruit.com/contribute-to-circuitpython-with-git-and-github/create-your-pull-request that gives a more in depth description and covers the process. That whole guide contains great information to get you started contributing to CircuitPython libraries.

[b-blake]

@FoamyGuy OK, I have not modified your code to add this feature. I looked and am not sure where in the code a byte is actually written to the EEPROM. So I guess I will have to leave it as an idea the code manager considers for implementation. Thank you for the offer.

[FoamyGuy]

@b-blake It writes to the EEPROM ultimately from here:

Adafruit_CircuitPython_24LC32/adafruit_24lc32.py

Lines 133 to 154 in f8fc83f

	def __setitem__(self, address, value):
	"""Write the value at the given starting index.
	.. code-block:: python
	# write single index
	fram[0] = 1
	# write values 0 thru 4 with a list
	fram[0:4] = [0,1,2,3]
	"""
	if self.write_protected:
	raise RuntimeError("FRAM currently write protected.")
	if isinstance(address, int):
	if not isinstance(value, int):
	raise ValueError("Data stored in an address must be an integer 0-255")
	if not 0 <= address < self._max_size:
	raise ValueError(
	"Address '{0}' out of range. It must be 0 <= address < {1}.".format(
	address, self._max_size
	)
	)
	self._write(address, value, self._wraparound)

The line near the end does the writing specifically. It could be put inside of an if statement that checks the address / value and then only calls _write if they aren't the same already.

[b-blake]

FG,

I found that line/part. Where is a byte read?
I have yet to figure out how to read the byte that is about to be written.
I don't find a self._read(address) or similar that I can call and test on.
I figure I am 50% fluent in Python/CircuitPython. ;-)

BBB

[FoamyGuy]

I think you can read a value using square brackets just like it's done in the examples.

self[address] should read the value at the given address.

[b-blake]

Thank you for the tip, however whoever wrote the code is smarter than me.
The self._write() call only handle's individual bytes. bytearrays are handled someplace else.
buffer = self[address] did not work. The code stopped at the new line of code, no error thrown.