• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 1048 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TCA9509: EN pin HIGH and no A side to B side communication

Shmuel Twig
Prodigy 10 points

Part Number: TCA9509
Other Parts Discussed in Thread: TCA9517

Hello,

I am an Independent developer.

Attached is the Schematics of the Circuit.

I am using an Atmega 328P to drive a capacitive CHIP (cy8mbr3116) using The TCA9509.

I am trying to understand if there is a mistake in my circuit or in my code.

EN pin receives a logic high (5v measured at pin) and sdaa and scla do not go through to scab and sclb. and no i2 device is scanned by code.

sdaa and scla signal readings behave different from sdab and sclb.

Thank you,
Sam



  • 0
    TI__Guru* 80711 points

    Hey Sam,

    I see a two potential problems.

    1) This device may not allow for VccA and VccB to be the same voltage.

    reference:

    The last comment is by a design engineer likely the one who designed the device).

    2) It looks like you are using pull up resistors on A side, which is not allowed by this device. The device it's own current source and the device detects whether the A side has current entering or leaving to determine where the zeros are coming from. Please remove any pull ups from the PCB on A side as this is likely the problem.

    If you are having issues with point number one, I would recommend TCA9517 as a pin to pin replacement and uses both pull up resistors so you won't run into issues like point number 2.

    ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

    "EN pin receives a logic high (5v measured at pin) and sdaa and scla do not go through to scab and sclb. and no i2 device is scanned by code."

    -Do you mean B side latches at Vcc or GND?

    "sdaa and scla signal readings behave different from sdab and sclb."

    -Can I see a scope shot?

    Thanks,

    -Bobby