UCD90120: UCD90120 I2C problem

Hi

From the waveform, it does not seem that your host support I2C clock stretching.

Could you confirm this?

Regards

Yihe

Hi 

Ok, I will confirm it. If our master doesn't support clock stretching, can we solve this issue on UCD90120? 

Thanks

Owen

Hi

unfortunately, the host must support clock stretching in order to have a reliable communication. 

Regards

Yihe 

Hi 

Our Host device supports I2C clock stretching. I can't understand why UCD90120 triggers clock stretching when we use Linux command i2cdetect ?

Thanks,

Owen

Hi 

Thanks, I check the detect waveform just like you said.

I had another two questions about stretching > if clock stretching happened can we use i2cget command to get the waveform?

the other question is when we use a logic analyzer to check the waveform, the clock stretching happened, should we do something on our host device?

and after timeout is 0xff  normal condition?

Thanks,

Owen

Update the question. 

We can use i2cset to catch waveform, but I2cget always occurs clock stretching. 

Thanks,

Owen

Hi

I am not sure what you are trying to do. But the bottom line that there is always a clock stretching from UCD and host has to ensue that they follow the right protocol to communicate

Otherwise there could be a communication issues

regards

Yihe

Hi 

Did you mean that UCD only can realize PMBus protocol format like 

If we send original I2C formats, it may cause UCD read failure.

Thanks,

Owen