The Theory
A counter is very useful for timed circuits. Add a standard clock that runs at some specific frequency and now you can create a stopwatch, clock or any other type of useful timing circuit. The counter we'll design will be only an incrementing circuit with the capability to be a decrementing circuit as well.
The Circuit
Below is a picture of the RTL Viewer Schematic generated by Quartus II. Compared to the previous UP2 based tutorial the schematic has become notably larger. Click on the picture to see the full schematic.
RTL Viewer Schematic
View Full Schematic
The output that all the inputs create is for the 8 LEDs on the board as well as the two different 7-segment displays. The counter value is displayed on both simultaneously. Concurrency is the chief advantage that VHDL offers and this is a simple example of how two things are happening at the same time in the same circuit.
A counter is very useful for timed circuits. Add a standard clock that runs at some specific frequency and now you can create a stopwatch, clock or any other type of useful timing circuit. The counter we'll design will be only an incrementing circuit with the capability to be a decrementing circuit as well.
The Circuit
Below is a picture of the RTL Viewer Schematic generated by Quartus II. Compared to the previous UP2 based tutorial the schematic has become notably larger. Click on the picture to see the full schematic.
View Full Schematic
The output that all the inputs create is for the 8 LEDs on the board as well as the two different 7-segment displays. The counter value is displayed on both simultaneously. Concurrency is the chief advantage that VHDL offers and this is a simple example of how two things are happening at the same time in the same circuit.