Serial decoding I2C

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Serial decoding I2C

Post by OliverDOM »


I Am using a PicooScope 3406D MSO with PicoScope® 6 Version:
I am trying to decode I2C communication as you can see in my attached screenshots.
SCL = red
ADA = blue

The address and data is decoded correctly but I am not sure how to interpret the acknowledge.
In the diagramm there is an ACK for both the address and data byte as SDA is low during the 9th clock cycle.
But in the table below it says "Address Ack = 0".

Does it mean the decoder does not recognise any ACK or is it the only the represented bit value of ACK or NACK. So if there would be a NACK it would be "Address Ack = 1".
This reverse logic is quite confusing, especially when you see that the read/write bit is resolved in an extra column "R/W".

I hope someone can clarify.

Thanks and best regards


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Re: Serial decoding I2C

Post by bennog »

your sample rate is too low. Set sample rate at least 5-10 times the bit rate.
you can see the sample rate if you open property's window.


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