TCA9539-Q1: question about INT pin behavior when RESET pull down

junsong gu

Part Number: TCA9539-Q1
Other Parts Discussed in Thread: TCA9539

HI TI Expert,

as sch show below, during MCU standby mode, TCA9539 reset pin will be pull down, will the INT pin still action correctly when there is a tigger on input port ?

Junsong_Gu

over 2 years ago

+1 Clemens Ladisch over 2 years ago

Guru 319830 points

While /RESET is low, the I/O expander is completely inactive. The input ports will detect changes only after /RESET goes high.

0 junsong gu over 2 years ago in reply to Clemens Ladisch

Prodigy 170 points

Got it，thanks

0 junsong gu over 2 years ago in reply to Clemens Ladisch

Prodigy 170 points

Can we float the reset pin?

0 Clemens Ladisch over 2 years ago in reply to junsong gu

Guru 319830 points

No, it does not have an internal pull-up.

0 Jack Guan over 2 years ago in reply to Clemens Ladisch

TI__Mastermind 47281 points

Hey Junsong,

Clemens' is correct here. The /RESET pin is active low so a pullup resistor is required if the /RESET pin is not in active use. Let us know if you have any further questions.

Regards,

Jack

Interface

Interface forum

TCA9539-Q1: question about INT pin behavior when RESET pull down