GPIO drive strength

[Frikkie Badenhorst]

Hi there,

We are developing on the NRF5340, and have a question regarding the drive strength that can be set on a GPIO pin using the PIN_CNF register.

However we can not find any information on what exactly each drive strength setting does and the current we expect it to draw. 

Could you please point us to some more information?

Kind regards,

Frikkie

[Jared]

Hi,

However we can not find any information on what exactly each drive strength setting does and the current we expect it to draw. 

The current is specified in the GPIO Electrical specification here.

High drive means that you can sink/source about 10 mA.

Standard drive means that you can sink/source about 2 mA

Disconnected means that the pin isn't connected to anything internally, which is equal to High-Z floating. 

D0H1 means that the pin will be disconnected when it's set to 0 and put in High drive when it's set to 1.

PIN_CNF

regards
Jared

[Frikkie Badenhorst]

Thanks for referring me to the electrical specs. We overlooked that information.

However it is still unclear what exactly all the drive configurations mean?

For example wat does S0S1 "standard 0 and standard 1" mean? From your previous post I understand that this means you can sink/source 2 mA when the it is set both to 0 and 1? Is this correct?

If this is the case, what then if we want to use the pin as an output, and writing the pin to 0 should turn it off. Surely it should not be able to source 2mA still? Hope you understand the confusion here as the documentation is not clear at all

Regards,

Frikkie

[Jared]

Frikkie Badenhorst said:

For example wat does S0S1 "standard 0 and standard 1" mean? From your previous post I understand that this means you can sink/source 2 mA when the it is set both to 0 and 1? Is this correct?

It means that if the pin is set to input, you can sink current up to 2 mA.

If the pin is set to output and '1', then you can source current up to 2 mA. 

Frikkie Badenhorst said:

If this is the case, what then if we want to use the pin as an output, and writing the pin to 0 should turn it off. Surely it should not be able to source 2mA still?

Yes, no current will flow out from the pin in that case. However, if it's set to 1 then current up to 2 mA can flow out from the pin.

regards

Jared 

[Frikkie Badenhorst]

Thanks Jared.

I am however sure that this can be a lot more clear in the documentation.

[Jared]

I totally agree, I'll report this internally.

Thank you!