PCA9548A: Application of PCA9548A I2C fail

Kay Chen53

Part Number: PCA9548A

Hi there:

We'd like to check an application for PCA9548A, the following is their schematic.

Issue description, for U8 is our PCA9548A, to replace nxp's PCA9548A (U5 & U6) . But sometimes reading I2C would fail at U5 & U6 those 2 location.

any suggestion we could check firstly about their schematic or risk for using our PCA9548A to replace the other?

U6.pdf

over 7 years ago

0 fhoude over 7 years ago

TI__Mastermind 23326 points

Hello Kay,

I have a couple of questions.

1) Is their a pull up resistor for the nRESET pin that is not shown in this page of the schematic?

2) Where are all the pullup resistors on all the channels (Channel 0 to Channel 7)? Is it on some other page? Pullups on the channels is required if you plan on being able to communicate to the slaves attached to the channels.

Can you explain in detail what a "fail" means when reading? Do they mean the register read for the PCA9548A doesn't match what they wrote to it previously? Can they show waveforms of the transactions of writing and reading? It my experience, people sometimes forget to generate a stop condition after writing to a register to our devices. We can verify this with waveforms of write and read transactions.

-Francis Houde

0 Miguel Robertson over 7 years ago in reply to fhoude

TI__Guru 62920 points

Hi Kay,

Just wanted to check back in on this - have you had a chance to take a look at Francis's questions above?

Regards,
Max

0 Kay Chen53 over 7 years ago in reply to Miguel Robertson

Expert 2225 points

Hi Francis & Max:

Thanks again, we've discussed with RD side for those concern. But currently not get feedback yet.

Still thanks anyway for your suggestion.

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PCA9548A: Application of PCA9548A I2C fail