You are here

I2C Bus

I2C is a two-wired serial bus developed by Philips (now NXP) in the early '80s. Currently, the I2C bus is widely used for interconnection of single-chip microcontrollers, memory chips (EEPROM), analogue-to-digital and digital-to-analog converters, pressure and temperature sensors as well as a variety of other peripheral devices.

I2C bus specification describes four operating speed categories for bidirectional data transfer:

Standard-mode (Sm) a bit rate up to 100 kbit/s
Fast-mode (Fm) a bit rate up to 400 kbit/s
Fast-mode Plus (Fm+) a bit rate up to 1 Mbit/s
High-speed mode (Hs-mode) a bit rate up to 3.4 Mbit/s

I2C bus uses two lines - SDA (data line) and SCL (clock line).

I2C Bus

The data is transmitted between two devices - Master and Slave. Master initiates data transfer and generates the synchronization signals. Slave begins data transmission only after master requests it.

Multiple master and slave devices can be connected to the same bus. Later we will discuss the role of each of them, but now it is important to understand how they can transmit data on the same wire, avoiding conflicts.

All devices are connected to the bus via an open collector or open drain. With this connection, the device may output either a logic zero or nothing at all (the output is in the high impedance state).

If outputs of all connected devices are in the high-impedance state, the two external pull-up resistors Rp will hold the lines at high voltage level (logic 1 state). A typical value for these resistors ranges from 1 K to 10 K. 

I2C bus multimaster

If one or more devices output logic 0, they set the line voltage to low level. The bus is considered to be free when no transmission happens and both lines are in the logic 1 state.

In later chapters, we will examine in detail a variety of options for connecting devices to the I2C bus. Now let's move on and study the I2C protocol by the example of one data byte transmission from the I2C bus master to the slave.

I2C Data Byte Transfer

This waveform can be divided into seven parts:

  • generation of the START (S) condition
  • transmission of the slave device address (0x51)
  • data direction bit (read or write)
  • acknowledgment (ACK) of the slave device address
  • transmission of the data byte
  • acknowledgment (ACK) of the data byte
  • generation of the STOP (P) condition

We will discuss all seven parts of this waveform in I2C Byte Transfer section. Now lets turn our attention to the transmission of one data bit by the I2C bus.​

 

I2C Bit

While transferring data, values on the SDA line are changed when the SCL line is LOW. When the SCL line is HIGH, the receiver reads the data bit (the state of the SDA line). At this point the value of the SDA line must be stable.

Rating: 
Average: 5 (6 votes)
Raina Rawlings Raina
Raina Rawlings Raina's picture
Offline
Last seen: 10 months 1 week ago
Joined: 11/11/2018 - 09:10
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

That is really attention-grabbing, You're a very professional blogger.
I've joined your rss feed and look ahead to seeking
more of your great post. Additionally, I have shared your <a href="http://prima-ballett.de/user/RogelioEdmondson/">net gambling site</a> in my social networks

Chu Sanford Chu
Chu Sanford Chu's picture
Offline
Last seen: 4 months 8 hours ago
Joined: 01/24/2019 - 14:31
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

Amazing! Its truly amazing paragraph, I have got much clear idea regaqrding
from this paragraph.

My site: buzzfeed diy teeth wwhitening ( Forrest -
http://forum.sevencode.ir/entry.php?72713-What-You-Should-Find-Out-About-Caring-For-Your-Tooth )

Chu Sanford Chu
Chu Sanford Chu's picture
Offline
Last seen: 4 months 8 hours ago
Joined: 01/24/2019 - 14:31
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

Amazing! Its truly amazing paragraph, Ihave got
much clear idea regardding from this paragraph.

mywebsite :: buszfeed diy teeth whitening ( Forrest - http://forum.sevencode.ir/entry.php?72713-What-You-Should-Find-Out-About-Caring-For-Your-Toith )

Dante Bleau Dante
Dante Bleau Dante's picture
Offline
Last seen: 7 months 14 hours ago
Joined: 02/21/2019 - 06:31
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

Hey! I know this is kinda off topic but I was wondering if you knew where I could get
a captcha plugin for my comment form? I'm using the same blog platform as yours and I'm having trouble
finding one? Thanks a lot! viagra prices - https://charter.education/scandal/index.php?title=Viagra_Coupons_-_The_Story

Dante Bleau Dante
Dante Bleau Dante's picture
Offline
Last seen: 7 months 14 hours ago
Joined: 02/21/2019 - 06:31
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

Hey! I know this is kinda off topic but I was wondering if you knew where
I could get a captcha plugin for my comment form? I'm using the
same blog platform as yours and I'm having trouble finding one?
Thanks a lot! viagra prices - https://charter.education/scandal/index.php?title=Viagra_Coupons_-_The_Story

Linette Benjami...
Linette Benjamin Linette's picture
Offline
Last seen: 6 months 4 weeks ago
Joined: 02/23/2019 - 06:31
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

The other day, while I was at work, my cousin stole my apple ipad and tested to see if it can survive a thirty foot drop,
just so she can be a youtube sensation. My iPad is
now broken and she has 83 views. I know this is totally off
topic but I had to share it with someone! viagra - https://forum.arthas-legion.de/user/17462-geosonia2/

Linette Benjami...
Linette Benjamin Linette's picture
Offline
Last seen: 6 months 4 weeks ago
Joined: 02/23/2019 - 06:31
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

The other day, while I was at work, my cousin stole my apple
ipad and tested to see if it can survive a thirty
foot drop, just so she can be a youtube sensation. My iPad is now broken and she has
83 views. I know this is totally off topic but
I had to share it with someone! viagra - https://forum.arthas-legion.de/user/17462-geosonia2/

Deanna Gholson ...
Deanna Gholson Deanna's picture
Offline
Last seen: 6 months 4 weeks ago
Joined: 02/23/2019 - 14:37
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

I am really inspired along with your writing talents and also with the structure for
your blog. Is that this a paid theme or did you customize it your
self? Either way keep up the excellent quality writing,
it is uncommon to see a nice blog like this one today..

My web-site: Deniz Nakliye - https://www.dmgtransport.com/

Deanna Gholson ...
Deanna Gholson Deanna's picture
Offline
Last seen: 6 months 4 weeks ago
Joined: 02/23/2019 - 14:37
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

I am really inspired along with your writing talents and also with the structure for your blog.
Is that this a paid theme or did you customize it your self?
Either way keep up the excellent quality writing, it is
uncommon to see a nice blog like this one today..

Here is my site; Deniz Nakliye - https://www.dmgtransport.com/

Madeleine Fitzs...
Madeleine Fitzsimons Madeleine's picture
Offline
Last seen: 6 months 1 week ago
Joined: 03/09/2019 - 20:48
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

Thankfulness to my father who told me about thgis webpage, this webpage is really awesome.

my web page; Adana No Touch - https://cukurovagoz.com.tr/

Madeleine Fitzs...
Madeleine Fitzsimons Madeleine's picture
Offline
Last seen: 6 months 1 week ago
Joined: 03/09/2019 - 20:48
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

Thankfulness to my father who told me about this webpage, this webpage is really awesome.

My blog; Adana No Touch - https://cukurovagoz.com.tr/

Fatima Cowart Fatima
Fatima Cowart Fatima's picture
Offline
Last seen: 4 months 3 weeks ago
Joined: 04/25/2019 - 11:53
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

This iis my first time pay a visit at ere and i am genuinely happy to read all aat single place.

my blg :: ladies gold ings with prices; Mindy - http://bling.ie/ ,

Fatima Cowart Fatima
Fatima Cowart Fatima's picture
Offline
Last seen: 4 months 3 weeks ago
Joined: 04/25/2019 - 11:53
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

This is mmy fitst time pay a visit at here and i am genuinely happy too read all at single place.

Check out myy blopg post :: ladies gold rings wikth prices;
Mindy - http://bling.ie/ ,

Kenny Buie Kenny
Kenny Buie Kenny's picture
Offline
Last seen: 4 months 1 week ago
Joined: 05/12/2019 - 13:38
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

Goood day! I just want to give you a big thumbs up for the excellent info you hhave got here on this post.
I am returning tto your blog for more soon.

Also visit my web-site :: diyet tavsiyeleri - https://Beklentiler.com/

Kenny Buie Kenny
Kenny Buie Kenny's picture
Offline
Last seen: 4 months 1 week ago
Joined: 05/12/2019 - 13:38
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

Goodd day! I just want to give you a big thumbs up foor the excellent
info you have got here on this post. I am returning tto you blog for moree soon.

my homepage diyet tavsiyeleri - https://Beklentiler.com/

Lupita Dempsey ...
Lupita Dempsey Lupita's picture
Offline
Last seen: 3 months 1 week ago
Joined: 06/09/2019 - 12:55
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

Greetings! Quick question that's completely ooff topic.

Do youu know how to make your site mobile friendly?
My web site looks weird when viewig from my iphone.
I'm trying to ffind a theme or plugin that
might be able to fix this issue. If you have any suggestions, pleasse share.
Thanks!

Here is my wweb site - Market Cross Dentistrty Clicic -
http://dentistireland.webflow.io/

Lupita Dempsey ...
Lupita Dempsey Lupita's picture
Offline
Last seen: 3 months 1 week ago
Joined: 06/09/2019 - 12:55
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

Greetings! Quiick question that's completely off topic.
Do you know how to make your site mobile friendly?
My web site lookss weird when viewing from my iphone.
I'm trying to find a theme or pluugin that might be able
to fix this issue. If you hhave any suggestions, please share.

Thanks!

Also visit my weblog - Market Cross Dentistry Clicnic - http://dentistireland.webflow.io/

Shelli Perea Shelli
Shelli Perea Shelli's picture
Offline
Last seen: 3 months 1 week ago
Joined: 06/14/2019 - 11:10
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

I drop a leave a respoonse whenever I like a post on a blog or I have something to valuable
to contribute to the discussion. Usually it iss caused by the fire displayed in the post I
read. And on this artricle I2C Bus | USB-I2C/SPI/GPIO Interface Adapters.
I was actually moved enough to post a thought :-P I actually doo have a couple of questions for you if it's okay.

Is it only me or do a few of the remarks appear like left
by brain dead people? :-P And, iif you are writing on otherr online sites, I'd
like to follow you. Could you list every one of your communal pages
like your Facebook page, twitter feed, or
linkedin profile?

Here is my blog post; engagement ring forr woman - Claudette - http://bling.ie/engagement-ring-for-woman-14137.html
-

Shelli Perea Shelli
Shelli Perea Shelli's picture
Offline
Last seen: 3 months 1 week ago
Joined: 06/14/2019 - 11:10
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

I drop a leave a response whenever I like a post on a blog or I have something to valuable to
contribute to the discussion. Usually it is cajsed by the fire
displayed in the post I read. And on this article I2C Bus | USB-I2C/SPI/GPIO Interface Adapters.

I wwas actually moved enough to post a tthought :-P I actually ddo have
a couple of questions for you if it's okay. Is iit only me or
do a few of the remarks appear like left by brain dezd people?
:-P And, if you aree writing on other online sites, I'd like to follow you.
Could you list every one of your communal pages like your Facebook page, twitter feed, orr linkedin profile?

Visit my web-site ... engagement ring ffor wooman - Claudette - http://bling.ie/engagement-ring-for-woman-14137.html -

Charlie MacGill...
Charlie MacGillivray Charlie's picture
Offline
Last seen: 3 months 1 week ago
Joined: 06/14/2019 - 19:53
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

This excellent website really has all of the information and facts I
eeded about this subject and didn't know who to ask.

Review my homepage - men's ring style guide, Bernard - http://bling.ie/men's-ring-style-guide-4934.html ,

Charlie MacGill...
Charlie MacGillivray Charlie's picture
Offline
Last seen: 3 months 1 week ago
Joined: 06/14/2019 - 19:53
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

This excellent website really has aall of thee information and facts I needed about
thos subject aand didn't know who to ask.

Visit myy page ... men's ring style guide, Bernard - http://bling.ie/men's-ring-style-guide-4934.html ,

Lawrence Osborn...
Lawrence Osborne Lawrence's picture
Offline
Last seen: 3 months 6 days ago
Joined: 06/14/2019 - 23:36
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

I love your blog.. very nice colors & theme. Did yoou
make this website yourself or did you hire someone to do it for you?
Plz respond as I'm lpoking to construct my own blog and would like to find out
where u got this from. thanks a lot

My homepage ... gold ring designs without diamond ( Julianne - http://bling.ie/gold-ring-designs-without-diamond-22559.html )

Lawrence Osborn...
Lawrence Osborne Lawrence's picture
Offline
Last seen: 3 months 6 days ago
Joined: 06/14/2019 - 23:36
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

I lolve your blog.. very nice colofs & theme. Did you make this website yourself
or did yoou hire someone to do it for you? Pllz respond as I'm
looking to construct my own blog and wokuld lile to find out where u
got this from. thanks a lot

Also visit my weblog gold ring designs without diamond ( Julianne - http://bling.ie/gold-ring-designs-without-diamond-22559.html )

Sam Lieb Sam
Sam Lieb Sam's picture
Offline
Last seen: 3 months 3 days ago
Joined: 06/18/2019 - 03:41
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

I'm truly enjoying the design and layout of your
website. It's a very easy on the eyes which makes it much more enjoyable for
me to come here and visit more often. Did you hire out a designer to create your theme?

Exceptional work!

My web blog - Bianca - http://liquid-space.net/ls/index.php/Benutzer:NanCrabtree5

Sam Lieb Sam
Sam Lieb Sam's picture
Offline
Last seen: 3 months 3 days ago
Joined: 06/18/2019 - 03:41
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

I'm truly enjoying the design and layout of your website.
It's a very easy on the eyes which makes it much more enjoyable for me to come
here and visit more often. Did you hire out a designer to create
your theme? Exceptional work!

my web blog; Bianca - http://liquid-space.net/ls/index.php/Benutzer:NanCrabtree5

Hilda McCree Hilda
Hilda McCree Hilda's picture
Offline
Last seen: 3 months 3 days ago
Joined: 06/18/2019 - 08:08
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

Very good info. Lucky me I came across your blog by chance (stumbleupon).
I've saved it for later!

Feel free to visit my blog post Quinn - https://128.227.67.21/Content_Material_Technique

Hilda McCree Hilda
Hilda McCree Hilda's picture
Offline
Last seen: 3 months 3 days ago
Joined: 06/18/2019 - 08:08
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

Very good info. Lucky me I came across your blog by chance
(stumbleupon). I've saved it for later!

My site; Quinn - https://128.227.67.21/Content_Material_Technique

Annetta Whish A...
Annetta Whish Annetta's picture
Offline
Last seen: 2 months 1 week ago
Joined: 07/11/2019 - 22:15
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

Hi! I just wanted to ask if you ever have any problems with hackers?

My last blog (wordpress) was hacked and I ended up losing several
weeks of hard work due to no data backup. Do you have any methods to stop hackers?

Stop by my web blog; sex hattı - http://sohbet40.ml

Annetta Whish A...
Annetta Whish Annetta's picture
Offline
Last seen: 2 months 1 week ago
Joined: 07/11/2019 - 22:15
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

Hi! I just wanted to ask if you ever have any problems with hackers?
My last blog (wordpress) was hacked and I ended up losing several weeks of
hard work due to no data backup. Do you have any methods to
stop hackers?

Feel free to visit my web-site: sex hattı - http://sohbet40.ml

Valorie Kirklan...
Valorie Kirkland Valorie's picture
Offline
Last seen: 2 months 1 week ago
Joined: 07/14/2019 - 13:18
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

This information is invaluable. Where can I find out more?

Here is my webpage Poker Online ( mb.tengfeiliren.com - http://mb.tengfeiliren.com/comment/html/?59160.html )

Valorie Kirklan...
Valorie Kirkland Valorie's picture
Offline
Last seen: 2 months 1 week ago
Joined: 07/14/2019 - 13:18
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

This information is invaluable. Where can I find out more?

Here is my site: Poker Online ( mb.tengfeiliren.com - http://mb.tengfeiliren.com/comment/html/?59160.html )

Shawnee Delgadi...
Shawnee Delgadillo Shawnee's picture
Offline
Last seen: 2 months 1 day ago
Joined: 07/20/2019 - 10:11
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

obviously like your web-site however yoou have to take a
look at the spelling on quite a few of your posts.
Many of them arre rife with spelling problems and I in finding it verry
bothersome to inform the truth nevertheless I'll certainly come bac again.

Here is my website: ring fits, engagementrings.life
-http://engagementrings.life/ ,

Shawnee Delgadi...
Shawnee Delgadillo Shawnee's picture
Offline
Last seen: 2 months 1 day ago
Joined: 07/20/2019 - 10:11
I2C Bus | USB-I2C/SPI/GPIO Interface Adapters

obviously like your web-site however you
have to take a look at the spelling on quite a few of
your posts. Many of them are rife with spelling problems and I in finding it very bothersome to inform the truth nevertheless
I'll certainly come back again.

my web site: ring fits, engagementrings.life - http://engagementrings.life/ ,

Languages

User login