MSP430FR2433: Digital I/O terminals during Power-Off

Takayuki Miyazaki

Genius 10120 points

Part Number: MSP430FR2433

Hi Experts,

We received inquiry about Digital I/O terminals during power-supply is OFF (Vcc= 0V)

In the case of Vcc=0 (Powered-Off) , digital I/O terminals have internal pulldown enabled ?
If internal pulldown are enabled in Power-off-state, is there any way to disable those internal pulldown ?

( Since it’s power-off, we believe there is no way to control those terminal state )

Customer does not have any issue, those are just questions.

I really appreciate if you will be able to share your advice/comments on those questions.

Best regards,

Miyazaki

over 6 years ago

0 Dennis Lehman over 6 years ago

TI__Guru 71216 points

Hello Miyazaki,
You are correct. When power is removed (0v), there is no control of the digital I/O terminals and internal pulldowns are not enabled.

0 Keith Barkley over 6 years ago

Guru 42215 points

But note that if you apply voltage to a GPIO - or any pin! - while the chip is off it is possible to power the chip through the ESD diodes, so it is bad practice to apply voltage to the pins when the Vdd = 0.

0 George Hug over 6 years ago in reply to Keith Barkley

Genius 4350 points

Yes indeed. And one possible outcome is that the current flowing through the diode will charge up the capacitor on Vcc, and the chip will turn ON. Here's a video on powering an MSP430 through the protection diodes:

https://www.youtube.com/watch?v=2yFh7Vv0Paw

And I'm embarrassed to say I have personally flashed firmware via JTAG to a G2231 with no power applied to the Vcc pin. And the flashing was successful. Not a practice recommended by TI. :-)

0 Dennis Lehman over 6 years ago in reply to George Hug

TI__Guru 71216 points

Hello Miyazaki,

Keith and George make very good points. I hope your customer is aware not to violate the GPIO pins.
I will go ahead and close this thread since it sounds like your customer's question has been addressed.
You can re-open this if you have additional questions on this topic.

0 Takayuki Miyazaki over 6 years ago in reply to Dennis Lehman

TI__Genius 10120 points

Hello Dennis, Keith and George

Thanks for your clarification and attention.
Regarding Internal EDS diode protection, although it was other device, I also had this experience.

Thanks again and best regards,
Miyazaki

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MSP430FR2433: Digital I/O terminals during Power-Off