CC2651R3SIPA: Is the state of the DIO pin at power-on (before initialisation) HI-z?

Dear David

Thank you for your advice, and I have one more question about your advice.

> By default, the I/O driver (output) and input buffer (input) are disabled.
> ~ safely be left unconnected (floating)

From the point of view of input buffer, if input buffer is floating, input buffer is weak from external noise and something.

Might it be happened latch-up? or are there any other protections?

Hello,

They are in high impedance mode, therefore they can be left unconnected.

BR,

David.

Thank you for your reply.

As I understand it, when an input pin is floating and in a high-impedance state, it becomes susceptible to external noise, which could potentially trigger latch-up.

Is this understanding correct?

I’m particularly concerned that a floating input pin might cause latch-up due to external noise.

In CC2651R3SIPA, could you please explain why unconnected input pins are typically protected from latch-up, even though they may be exposed to noise?

Thanks.

Just following up on the question I sent earlier—any updates?
Regards.

Hello Toshio,

Apologies for the delay due to holidays. If the input pins are left unconnected/floating, it is recommended to configure the pull up/pull down to make sure they are in a known state.

BR,

David.

Thanks.

Regarding the state of DIO pins at power-on, before the MPU wakes up, the DIO direction (input/output) is not yet defined.
Based on your comments, which approach do you recommend?

> The I/O pin can safely be left unconnected (floating).
> It is recommended to configure a pull-up or pull-down resistor.

BR,

Hello TI teams,

Do you have any update about above question?

Since the DIO direction (input/output) is not yet defined before the MPU wakes up, would it be necessary to add an external pull-up or pull-down resistor to ensure the pin can be safely left floating?

BR,