TMP451: What's the exactly address for TMP451

Shaquille Chen

Intellectual 1770 points

Part Number: TMP451

Hi team,

Based on datasheet, slave address of TMP451 is 4Ch.

Based on the 8bit I2C, 99h for read and 98h for write.

Customer tried this address but get NACK, what's the possible issue.

Thanks

Shaq.

over 6 years ago

0 Amit Ashara over 6 years ago

TI__Guru**** 244400 points

Hello Shaq,

You are correct. The address for the TMP451 is 0x4C, which means that during a Write it will be 99h and during a read it shall be 98h.

It seems from the snapshot, that there is some transaction before the read is issued. Can you please provide a full snapshot of the transaction.

0 Min Hsien Li over 6 years ago in reply to Amit Ashara

Prodigy 50 points

Hi Amit,

I'm EC engineer from pegatron. Please refer to the full transaction pic below. There is no other transaction before "Start" condition.

Best regards

Tim / Pegatron corp.

0 Amit Ashara over 6 years ago in reply to Min Hsien Li

TI__Guru**** 244400 points

Hello Tim,

Looking at the waveform, there are two things which do not seem correct

1. The first SDA rise is too close to the first SCL fall edge which is for the Start condition
2. The SDA edges are too close to the SCL fall edges that it may not be meeting the timing.

If you can change the behavior of the I2C timing on the bus, that would be helpful.

0 Min Hsien Li over 6 years ago in reply to Amit Ashara

Prodigy 50 points

Hi Amit,
Thank you for your comment. We'll keep on tracking this.
thanks

Best regards
Tim / Pegatron corp.

0 Amit Ashara over 6 years ago in reply to Min Hsien Li

TI__Guru**** 244400 points

Hello Tim,

Is the interface bit-banged or is it being control via a MCU

0 Min Hsien Li over 6 years ago in reply to Amit Ashara

Prodigy 50 points

Hi Amit,
It's control via MCU.
thanks

Best regards
Tim / Pegatron corp.

0 Amit Ashara over 6 years ago in reply to Min Hsien Li

TI__Guru**** 244400 points

Hello Tim,

Ok, in that case the timings may not be controllable. I would suggest bit banging the address phase to see if the address is ACK'ed. Also can you check the timings that were suggested earlier to see if it is being maintained as per the datasheet.

0 Min Hsien Li over 6 years ago in reply to Amit Ashara

Prodigy 50 points

Hi Amit,

We have tried to use I2C generator but it's same result as MCU transcation.

And we also check first falling edge betweeen SDA and SCL but It seems also fit spec too.

thanks

Best regards

Tim / Pegatron corp.

0 Amit Ashara over 6 years ago in reply to Min Hsien Li

TI__Guru**** 244400 points

Hello Tim,

Since I cannot reproduce the issue on my side yet, there are somethings that we would need to check on your setup

1. Is the device powered correctly? Can you check at the supply pin of the device
2. What is the Vcc supply being used for the device?
3. Can you share your schematics for your design?

0 Min Hsien Li over 6 years ago in reply to Amit Ashara

Prodigy 50 points

Hi Amit,
Sure. I'll contact our EE to check these hardware setting with Shaquille.

Thank you for all your assistance and comment.

Best regards
Tim / Pegatron corp.

0 Amit Ashara over 6 years ago in reply to Min Hsien Li

TI__Guru**** 244400 points

Hello Tim,

Is there any update on this thread?

0 Shaquille Chen over 6 years ago in reply to Min Hsien Li

TI__Intellectual 1770 points

Hi Team,

We find some issue on the part on board. We fixed it after change a new part.

Thanks.
Shaq.

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TMP451: What's the exactly address for TMP451