S32K118 PIN

[wenfengyao]

We need to input the external high-low level signal to the 18 pin of the MCU in series with a diode. At the beginning, the pin is in the default state without configuration, and only the external interrupt is used. In this case, the MCU pin detected at low level has a voltage of 800 or 900mV; When this pin is configured to the input (floating) state, the detected MCU pin has a voltage of about 0V at low voltage.

Our software colleagues believe that the external interrupt input and the configuration pin input (floating) should be in a high resistance state, but the measured results are not the same, may I ask the specific difference between the two internal circuits? What causes the low level input to have a voltage difference?

The part number is FS32K118LAT0MLFT

[danielmartynek · Accepted solution]

Hi @wenfengyao,

It should be in HIGH-Z and the pin should read 0V in this case unless there is the internal pull-up enabled - which would explain the 900mV at the anode.

The pullup is enabled on PTC5 by default, for example.

Which pin do you use?

What is the usecase here?

Regards,

Daniel

[wenfengyao]

I just want to use PIN 18 PTC5 pin to do an interrupt input, so the default state of this pin is pull-up?

[danielmartynek]

Hi @wenfengyao,

PTC5 has internal pullup enabled by default out of reset.

Please refer to

S32K118 IO_Signal_Description_Input_Multiplexing.xlsx

IO SIgnal Table

Column S

Regards,

Daniel