Arduino pulseIn function doesn't work HTCC-AB02

I got a Problem with the measuring of a puls with my HTCC-AB02 on GPIO 5. I tried to measure the exact same signal with a arduino nano every and it worked. With the cubecell Board the serial monitor output says alway 0.

Here is the code:
int Input = 5;

void setup() {
Serial.begin(9600);
pinMode(Input, INPUT);
}

void loop() {

unsigned long period = pulseIn(Input, HIGH);
long frequenz = period;
Serial.println(frequenz);
delay(1); // delay in between reads for stability
}