Talk:I²C

message: I'm not sure how to do it but could someone else edit the page so that if "2-wire serial" or similar is searched for then this page comes up? FzerozeroT 21:25, 14 November 2006 (UTC)
replies: text: I think it can be done, whilst another 2-wire interface wouldn't be presented (then 2-wire serial, 2-wire redirects should be replaced by disambig). --Yuriy Lapitskiy 06:20, 15 November 2006 (UTC)
replies: text: Instead of "2-wire serial", it should be "3-wire", right? Same as those misleading descriptions of "1-wire" systems (which are actually 2-wire) which leave out the ground wire - totally misleading. KorgBoy (talk) 03:28, 3 May 2019 (UTC)
thread_title:  Synonyms 

message: Also I2C-RAMs are available, for instance the PCF8570 (Philips).
It is helpful for communication between processors or controllers.  —Preceding unsigned comment added by 80.156.43.1 (talk) 17:29, 30 October 2007 (UTC)
thread_title:  Proposal: Addition of I2C-RAM 

message: The articale states "As of October 1, 2006, no licensing fees are required to implement the I²C protocol". I'd be interested to know about licencing terms Philips used to require. I seemed to remember that you could implement the bus logic, just not call your device "i2c compatible" unless you wrote a cheque. Anyone know more on this ? Whenrybruce (talk) 23:16, 3 November 2008 (UTC)
replies: text: I believe i2c as a term was trademarked but the interface technique itself wasn't.  Thus you'd have companies developing the exact same thing and calling it "two wire interface" among others.  Intel developed their own version of i2c, changed the voltages, and called it smbus.  —Preceding unsigned comment added by 150.135.210.16 (talk) 01:21, 29 October 2010 (UTC)
replies: text: i2c was trademarked but that word mark has expired, see references. the word mark for 'i2c bus' is still effective as of this date: 70.189.92.82 (talk) 18:45, 23 February 2018 (UTC)
replies: text:  Also this may need clarifying as the page it references too ( I²C Licensing Information) states "A license is required for implementing an I2C interface on a chip (IC, ASIC, FPGA, etc)." Whereas the wiki page contradicts this saying "no licensing fees are required to implement the I²C protocol" Please could someone clarify/correct this? 81.155.87.216 (talk) 14:49, 24 February 2014 (UTC)
replies: text:  The PDF link provided by anonymous 81.155.87.216 editor was created in 2003, which is 11 years old.  At some point in the past months, I thought that I read that I2C no longer needs a license, but NXP does require a fee to add to their I2C Address Document...though I don't remember where I read it.  • Sbmeirow • Talk • 20:56, 24 February 2014 (UTC)
replies: text:  I agree that the referenced PDF says no such thing about licensing not being required, and in fact says the opposite. And as pointed out, the attached document dates to 2003, not 2006. The sentence should either be removed or fixed. 205.153.101.8 (talk) 14:57, 15 March 2016 (UTC)
thread_title:  Licensing 

message: I just made an edit to the code comments, to clarify what the macros do. That's because there is no SETSDA() or SETSCL() macros. The original coder assumed that the READSDA() and READSCL() macros could be used for this purpose, but did not clarify that for this to work, the macros must first set the pin to an input, to allow the signal to be pulled high by the external resistors.
I have made the simplest change to make this more clear, but a more clear change would be to add SET* macros, which are separate in purpose to the READ* macros.
As for the previous discussion about the usefulness of this code and whether it belongs on the page at all, I'd like to comment that it was useful  me, and should stay.....  I confirm the reading and writing of single bytes works. (Arbitration and restarts untested but look good.)  — Preceding unsigned comment added by Gibster777 (talk • contribs) 09:27, 11 April 2011 (UTC)
replies: text: I2C driver using bit bang http://www.embeddedrelated.com/showcode/334.php  — Preceding unsigned comment added by 72.205.252.194 (talk) 19:07, 28 March 2015 (UTC)
thread_title:  Code example cleared up 

message: I feel the READ macros should be detailed, otherwise readers may not understand that the pull-ups may require up to 320ns to act if there is a lot of capacitance on the SDA or SCL lines.  I suggest:
bool READSCL(void)   /* Set SCL as input and return current level of line, 0 or 1 */
{
	Set_SCL_As_Input();
	Wait( 500ns );
	return Get_SCL_Input();
}
And likewise for READSDA().  Hoptroff (talk) 15:57, 20 July 2011 (UTC)
thread_title:  Code example and line capacitance 

message: "Peripherals can also be added to or removed from the I²C bus while the system is running, which makes it ideal for applications that require hot swapping of components.[citation needed]"
This is implied by the fact that it is based on open-collector logic and the fact that you can't communicate with more than one device at a time...  Why do so many "citations needed" come from people who seemingly didn't read the articles?!71.196.246.113 (talk) 10:10, 5 August 2011 (UTC)
replies: text:  so you're saying it's original research? must be removed per WP:NOR  — Preceding unsigned comment added by 70.189.92.82 (talk) 18:51, 23 February 2018 (UTC)
thread_title:  Hot-swapping 

message: It should be noted somewhere the default values for circuits - for example, the Rp is usually 4.7 kohms
: They vary widely.  I just checked one board I have; 2.2K for some, and 47K (! not 4.7K !) on another branch of the tree.  Don't think we can give values like that; they're circuit dependent.  See the relevant specs. 69.226.236.175 (talk)  —Preceding undated comment added 23:10, 26 August 2009 (UTC)
replies: text:  I think we need to add a section to this article that talks about "Rp" pull-up resistors (or constant current source or ICs) and "Rs" series resistors.  I have noticed lots of confusion in blogs about this subject matter, so I think it would benefit everyone to have a dedicated section about it.  Please reply with your thoughts!  • Sbmeirow • Talk • 22:13, 4 December 2013 (UTC)
thread_title:  Propose a NEW Resistor Section 

message: Hello fellow Wikipedians,
I have just added archive links to  on I²C. Please take a moment to review my edit. If necessary, add  after the link to keep me from modifying it. Alternatively, you can add  to keep me off the page altogether. I made the following changes:
*Added archive https://web.archive.org/20150816211659/http://www.almico.com/speedfan.php to http://www.almico.com/speedfan.php
When you have finished reviewing my changes, please set the checked parameter below to true to let others know.
Cheers. —cyberbot IITalk to my owner:Online 18:57, 29 August 2015 (UTC)
thread_title:  External links modified 

message: I see there is a note encouraging editors to "improve readability" by turning the list into prose. Actually, speaking as someone who just visited this page to learn about I2C, the list is more helpful.  — Preceding unsigned comment added by 80.47.157.107 (talk) 11:15, 10 January 2021 (UTC)
thread_title:  Applications - list is better 

message: There is a lot of dense description of the protocol which can quickly get confusing. Signal diagrams like the one at https://www.beyond-circuits.com/wordpress/wp-content/uploads/2015/04/tutorial18_i2s_timing.png would be helpful. I tried to make some but my understanding of I2C is too weak. Matt-bacon-bcm (talk) 00:06, 17 December 2023 (UTC)
thread_title:  "Physical layer" section - Signal diagrams would be helpful