TPS65982: TPS65982ABZQZR Unused GPIO Pins

Edward Ouellette

Prodigy 100 points

Part Number: TPS65982

The datasheet states that an unused GPIO pin should be pulled-down through a 1 Mega Ohm resistor.

Can a single resistor be shared by multiple unused pins? If so, what's the limit on sharing? (N * i * 1 Meg < VIL ?)

Thanks,

over 6 years ago

0 Adam Mc Gaffin over 6 years ago

TI__Mastermind 30000 points

Hi Edward,

Each unused GPIO will need their own 1M pull down resistor.

0 Edward Ouellette over 6 years ago in reply to Adam Mc Gaffin

Prodigy 100 points

Adam,

Thanks for your fast reply.

I'm still unclear as to why each unused GPIO pin needs a separate 1 meg resistor...

If all pins initialize to inputs upon power up, why can't a single resistor be shared among several inputs?

Thanks,

0 Adam Mc Gaffin over 6 years ago in reply to Edward Ouellette

TI__Mastermind 30000 points

Hi Edward,

The design could work with having a common 1 meg pull down resistor, but all the reference schematics I have seen have their own 1 meg pulldown so that is what I know works. Is this a prototype board? Can try to implement a 0 ohm resistor scheme that allows for all of them to be pulled down via a single 1 meg resistor, as well as the option to where each unused GPIO has their own 1 meg resistor.

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TPS65982: TPS65982ABZQZR Unused GPIO Pins