Unused GPIOs in TCA6424A

Oscar Gomez Fuente

Expert 2066 points

Other Parts Discussed in Thread: TCA6424A, IO-EXPANDER-EVM

Hi everyone,

I read in the datasheet that Exposed pad has to be left electrically open. But I've got a doubt about the GPIOS that I don't use.

Have they been float ? or Have they been tied to GND?

Best regards.

over 9 years ago

0 Siby James over 9 years ago

TI__Expert 5140 points

Hi Oscar,

The TCA6424A has internal pullups, so the GPIOs that you do not use do not need a pullup to VCC. However, if you want to be extra careful, these unused pins can be externally pulled up to VCC.

Thanks,
Siby

0 Oscar Gomez Fuente over 9 years ago in reply to Siby James

Expert 2066 points

Hi James,

My problem was that when I was testing the IO-EXPANDER-EVM, if the unused pins weren't tied to GND, a lot of interrupts occurs on my linux platform. So I have to place a pull-down resistor on the unused pins to avoid this issue.

Best regards.

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Unused GPIOs in TCA6424A