I am a little confused about the GPIO input voltage thresholds for logical HIGH and LOW.
In S32K-DS datasheet, Section 5.3 DC electrical specifications at 3.3 V Range, it suggests:
After resolving that, the high low zones look like.
My confusion lies here. There is this band that seems to be either undefined or I am not able to fully understand the table.
Further, I had the following observations while testing voltage on an input pin on our custom board:
Config: The pin has an external 3V3 pull up and some intermediate circuit with voltage drop.
1. When internal pin pull is OFF.
- The voltage at pin is between ~1.65V - 2.0 V and it reads it as LOW (mostly, but not always).
2. When internal pin pull is PULL UP.
- The voltage at pin is ~1.85V - 2 V and it always reads it as HIGH.
The two voltage ranges lie in the unknown band I mentioned above so I am not really sure what to expect of it.
Any help is appreciated.