i2c comm speed is something you set but is normally 100kHz or 400kHz. This is well explained and defined in the i2c protocol.

I am sorry BobaMosfet but that is not the answer of my question. Please convenience me if I have asked wrong question

This may be clear


Please ask me if you don't understand anything in the hand made diagram

How much time i2c bus take to send data ?

 

How much time i2c bus take to send data ?

Any time you like down to a minimum set by the clock speed (defined by the I2C master). This clock is typically 100kHz or 400kHz but can be anything slower than the maximum that the slave can work at.
See: https://www.i2c-bus.org/speed/
"The speed grades (standard mode: 100 kbit/s, full speed: 400 kbit/s, fast mode: 1 mbit/s, high speed: 3,2 Mbit/s) are maximum ratings. Compliant hardware guaranties that it can handle transmission speed up to the maximum clock rate specified by the mode.
This does not imply that a transmission may not take place at any lower speed or even at a somewhat variable bit rate."

 

hi a,
This incorrect its 10 times longer.
E


Update
This DS1307 App PDF should help you.
E

 

You seem to be asking about Baud now, not Hertz, that's good. But for I2C , Baud rate is usually not used in the same context as it is used in RS-232 type communications, as explained in the attached document from the horse's mouth.

There is no better place to get that answer than I2C itself: https://www.i2c-bus.org/speed/ I have attached a highlighted copy. Note: There is a typo in the first sentence, "a synchronous" should be "asynchronous."

 

hi a,
This is a clip from that d/s. refer this timing diagram.
E

 

hi a,
This incorrect its 10 times longer.

My bad English

You seem to be asking about Baud now, not Hertz, that's good. But for I2C , Baud rate is usually not used in the same context as it is used in RS-232 type communications, as explained in the attached document from the horse's mouth.

it's hard to digest answers. all explanation say that transmission speed/communication doesn't exist when two devices exchanging data

In real life if you ask to computer engineer What's the data speed between two computers and they give answer speed is in kbps

I was asking the same question what is the speed of serial communication over i2c

 

I was asking the same question what is the speed of serial communication over i2c

There is no fixed answer to this question. It all depends on the particular choices made in the system design.

 

My bad English

it's hard to digest answers. all explanation say that transmission speed/communication doesn't exist when two devices exchanging data

In real life if you ask to computer engineer What's the data speed between two computers and they give answer speed is in kbps

I was asking the same question what is the speed of serial communication over i2c

You're problem is you are not understanding what we are saying. Period.

I know from my own i2c projects, it's easy to see the transmission speed by examining pulse-width on the scope and comparing that to the rate I told it to transmit at (400kHz)- SDA is the top trace, SCL is the bottom trace:



And in case you missed this point, I'll repeat myself: YOU set the speed at which i2c/twi communicates at (depending on MCU features). If you don't, it may be set for you as a default, but I don't know your environment.