TCA9554A: TCA9554APWR：How about the default output, low level or high level?

Lucas Ding

Part Number: TCA9554A

Hi team,

Could you please help look into the problem that if the default output of PCA9554APWR is low level or high level? I think from the datasheet, it should be high level, if so, do you have any recommendations to make a p2p replacement with low level?

Thanks.

over 6 years ago

0 Miguel Robertson over 6 years ago

TI__Guru 62920 points

Hi Lucas,

The IOs are configured as inputs by default. However, the default value in the output port register is 11111111, so if the inputs are switched to outputs without re-writing this register their output state will be high.

Regards,
Max

0 Lucas Ding over 6 years ago in reply to Miguel Robertson

TI__Prodigy 320 points

Hi Max,

Thanks for your info. This is what I replied to customer, how about any appropriate solutions to meet the default low output requirements?

0 Miguel Robertson over 6 years ago in reply to Lucas Ding

TI__Guru 62920 points

Hi Lucas,

Would it be possible to install pull-down resistors on the IOs? Since they are configured as inputs by default this would serve to bias the lines low. Then, prior to being configured as outputs you could first set the output port values to 0 instead of 1.

Regards,
Max

Interface

Interface forum

TCA9554A: TCA9554APWR：How about the default output, low level or high level?