• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 33 subscribers
  • Views 435 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.

TCA9555 / issue on using multiple

ACGUY
Guru 11170 points
Other Parts Discussed in Thread: TCA9555, TCA9406

Hi all,

Please let me know about TCA9555.
Our customer is using the TCA9555 and TCA9406 with CPU.
TCA9555 are two. Customer is manipulating TCA 9555 in parallel.

Please see the attached file.

CPU sent a slave-address to TCA9555(20h), ACK signal voltage of TCA9555（20h） doesn't rise to 3.3V.
For that reason, CPU can't communication with TCA9555（20h).

Customer tried to communication with TCA9555（21h). However, the result was the same.

When delete a TCA9555（20h), CPU able to be communication with TCA9555（21h). The reverse is also true.

Customer changed the slave-addresas from 21h to 26h.
The result was the same.

Question;
Is this device can't to use in multiple?

Regards,
Nagai

Issue_TCA9555.pdf

  • 0
    TI__Genius 16510 points

    Nagai-san,

    Do you have a schematic you can show, as well? I would like to see the state of the address pins.

    There is no reason you cannot have multiple TCA9555s on the same bus, as long as you make sure their addresses are different (with address pins). None of these devices are able to drive the SDA line high. They can only pull down or release it. So your sketched waveform seems to suggest a very high current load to get a high VOL.

    What are your pull-up resistor values (which I would also like to see a schematic for)?

  • 0 in reply to Jonathan Valdez
    Guru 11170 points
    I appreciate your cooperation.

    I got the schematics from customer. I'll send that to your e-mail address.
    I look forward your comment.

    Thanks,
    Y.Nagai