Basic simulink with arduino uno

Hi everyone

I'm trying to read digital input to simulink (matlab 2012).
I succeeded to use basic digital output - got a led to blink

but as for input - I connected digital input to a basic display in simulink (figure attached),
tried to give 5v on and off to pin8, but no matter what I do - the dispaly show 0

how can I fix it?

thank you

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