TCA9539: IO-EXPANDER I2C Operation

Chris Yorkey

Part Number: TCA9539

Team,

While this posted question was originally threaded on the Tiva forum, it might be better served here on the I2C/TCA forums:

Any comments welcomed please!

TY,

over 8 years ago

0 Chris Yorkey over 8 years ago

TI__Genius 15855 points

Note: On the TCA9xxx side, we do realize that the Read from Register sequence is much different than the Write to Register sequence. We've noted the extra repeated start bit and R/W bit in the Read sequence vs. the Write are in fact quite different.

TY,
CY

0 Miguel Robertson over 8 years ago in reply to Chris Yorkey

TI__Guru 62920 points

Hi Chris,

I agree with the comments in the thread that the expander may not be properly configured for outputs - have you had a chance to look more into that? I wanted to double-check before I dig too much deeper into the code.

Max

0 Chris Yorkey over 8 years ago in reply to Miguel Robertson

TI__Genius 15855 points

Hi Max,

Hold off for now, as we are working on this with the team at the moment.

I'd anticipate having it resolved shortly.

Thanks for following up. I'll reach out again if needed.

-Chris

0 Chris Yorkey over 8 years ago in reply to Chris Yorkey

TI__Genius 15855 points

Folks,

Turns out, the customer had a hardware problem with the IO-EXPANDER EVM itself. After replacing the EVM, it worked as expected.

Thanks for everyone's valuable input regardless. It helps to track this down.

CY

Interface

Interface forum

TCA9539: IO-EXPANDER I2C Operation