How to test stop bit of I2C in DUT?

Greetings!

I'm having a tad bit of a problem here. Someone wants to

evaluate the extent to which his/her IC's I2C block can identify a stop condition

[please see the attached picture for details].

I'm looking for the best method out there so any suggested solution would

be highly appreciated.

 

That would be all. Have a nice day!

 

Warm Regards,

Justin

Hi,

Data is transferred in sequences of 8 bits. The bits are placed on the SDA line starting with the MSB (Most Significant Bit). The SCL line is then pulsed high, then low. Remember that the chip cannot really drive the line high, it simply "lets go" of it and the resistor actually pulls it high. For every 8 bits transferred, the device receiving the data sends back an acknowledge bit, so there are actually 9 SCL clock pulses to transfer each 8 bit byte of data. If the receiving device sends back a low ACK bit, then it has received the data and is ready to accept another byte. If it sends back a high then it is indicating it cannot accept any further data and the master should terminate the transfer by sending a stop sequence.

You can refer to the references attached. Or check this http://www.robot-electronics.co.uk/i2c-tutorial

Can also check this out from Texas Instruments,

Hi Kevin,

Thank you for your reply.
Hmmm... yes, that is how I2C communication works.
Sorry, I think you misunderstood the attachment.
Its a picture of the stop condition only.

I can see and observe the entire wave sent in the SDA and SCL lines.
But how do I test the setup time for the stop bit, in
other words, how much time would it take until the stop condition
isn't detected by the IC? How can I test this??? How can I test its integrity???

Hello,
The easiest way I can think of to test the stop set up time would to be to use an I2C protocol analyzer that allows you to write test scripts for it. That way you can control the timing of the signals sent over the I2C lines and see how your device responds to various pauses before a stop bit is sent.

Basically you can vary the pause lengths before the stop bit is sent and see if the device responds as it should e.g. if you wrote data to a certain register, does it read back as it should? Does it respond to further commands?

It also seems like there should be some sort of timer that times out after awhile if a stop bit is not received.