О Clock Stretch на ADAU1452

About Clock Stretch on ADAU1452

Активно 4 Ответы 43 Просмотры 2016-10-11 Работа с SigmaDSP

Hi all,

I have a question.

Does ADAU1452 have a function "Clock Stretching" in I2C communication?

In the system, Master micro controller and slave SigmaDSP communicate.

I've taken a look at the datasheet p.12 "I2C Interface—Slave". 

But it does not say anything about it.

Could you help me out?

Best Regards,

Yuta M



guest replied
2 Years

Hi Dave,

Thank you for your opinion.

In my customer's system, the Sigma300 is slave device against a master micro contoroller they use.

In this sense, the slave port is what they are using.

>What I am not sure about is if the uC keeps the SCK low then at some point the DSP will see it as a corrupted >transmission and ignore it? I am not sure how the state machine is setup."

Anyway, the Sigma DSP does not have clock stretch function on it. So, if their master micro contoroller keeps SCK low by accident, the Sigma DSP does not care it and the communication between them would just be corrupted.

Best Regards,

Yuta M

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guest replied
2 Years

Hello Yuta,

This part has two ports, a master and a slave. The slave port is what is used by a micro-controller. So the DSP will always be a slave and will never try to drive the SCK line. What I am not sure about is if the uC keeps the SCK low then at some point the DSP will see it as a corrupted transmission and ignore it? I am not sure how the state machine is setup.

Now for the Master port. When it is enabled and transmitting it will transmit the data then it will let the SCK and SDA lines float. If another uC on the line pulls the SCK low then it should do nothing until it tries to communicate again. I do not think it will detect the collision and will try to transmit the data. So it is not setup for multi-master. So if you want a uC to look at the EEPROM, or another part on the I2C bus, then you must be certain that the DSP will not be using the bus. We intended for the DSP to be the only master on the bus.

Dave T

guest replied
2 Years

Hello Dave,

I really appreciate your very quick answer!

I understand that the device doesn't have the function.

Say this device is the master device and there is a micro controller as a slave.

If this uC keeps SCK low, how does this adau1452 react without the clock stretching?

im asking this just for my curiosity.

best regards

yuta m

guest replied
2 Years

Hello Yuta,

No, it does not support clock stretching for I2C.

Dave T

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