schematics
Hi
I was working on this FT232RL USB to Serial Converter Circuit and now, in a doubt one thing. I understand that NC pins in the schematics have a cross Sign on them,but i didn't get this Pin12 CBUS4. As seen, the rest of the other pins have a cross sign but not this one. Is it another way of representing NC pin or is it connect
Rather than just moving wires to change your inputs, it would be well worth your while to get a DIP switch and a bunch of resistors (or a SIP resistor network). I would hook the 7489 up as follows:
simulate this circuit – Schematic created using CircuitLab
The SIP network is nice because you can plug it into your breadboard right next to the DIP switch, eliminating a lot of wires. Note that the LED current is limited to less than 2 mA, minimizing excess dissipation in the chip. Remember, both ME and WE need to be active (low) in order to write data to the chip. As you said, you could just tie ME low with a wire for this test.
The only way I know is a net-tie. For example to connect Power_GND with Ana_GND in a defined way.
Best Answer
The "X" makes it visually clear that the pin is intentional left unconnected, any typically it conveys to the design rule checking not to flag the pin as an error or warning.
So, as shown, it will look the same on the netlist as the other NC pins but may cause errors or warnings when you run DRC.