Block diagram, pic18f2550

[Jiadong Yao]

I am reading the ssp part. But i don't understand the symbol. The normal gate has a additional circle. What is the function?

Thanks.

 

[Easyrider83]

The circle means that input is inverted.

 

[Jiadong Yao]

The circle means that input is inverted.

Yes,I know that. but what happened to the gate?? will the gate be disabled if it is 0?
Since the circle locates at the side of the gate, I still don't know what the effect it is.

 

[GrandAlf]

Gate/buffer is non inverting. Enable low = gate open. Enable high = gate closed. Active low in other words.

 

[milan.rajik]

It is a Tri state buffer with active low (bubbled) Enable pin.

 

[Jiadong Yao]

Got it, thank you