Logic Devices

 ( Updated to 0.4.15 )

Most logic components have a common group of properties to configure their inputs and outpus characteristics.

You can see/edit these properties in left panel "Properties" tab when the component is selected or by Right-Click on the Component and select "Properties".

Besides the typical "id" and "show id" properties common to all components there are a few properties about inputs and outputs:

  • Input High V: Minimum input voltage considered high state (high threshold).
  • Input Low V: Maximum input voltage considered low state (low threshold).
  • Input imped: Input impedance.
  • Out High V:   Output voltage for high state.
  • Out Low V:    Output voltage for low state.

Editing these properties you can "mimic" different logic families/technologies.

For example you if you want Schmitt trigger inputs just set the input voltages as required, for example: 3 Volt. for high threshold and 2 Volt. for low threshold.

Or you can configure input and output impedances to get different "Fan In" and Fan Out" characteritics.

There are other extra properties  in each component type. Lets have a look to each logic component characteristics:

- LogicGates:

  • Inverted: wether the output is inverted or not.
  • Open Collector: Output high state is high impedance.
  • Num Inputs: Number of inputs ot the gate (when applicable).

At a first sight looks like SimulIDE don't have INVERTER, NAND, NOR, NXOR gates. They are actually there, all you have to do is set the inverted propertie to "true":

Buffer has an extra option:
  • Tristate: Connects or disconnect the output.
When activated an output enable pin will appear.
This pin controls if the output is high impedance or not, when thi pin is high the output is high impedance, when low it acts as a normal buffer.

- Buses:

When you use multiple parallel lines sometimes is useful group them in buses.
SimulIDE provides a component to do that.
- Num Bits: set the number of bits of the Bus.
- Start Bit: set the initial bit, rest of bits will be numbered from this.

Bus lines are shown thicker than normal lines, and you can't connect normal to bus.