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Circuit Description

The MIDI footswitch controller yet again, but running the internally clocked FastPic16C84 microcontroller model and using our special multiplexed seven-segment display simulation models. These display simulation models internally keep statistics of how long each display segment was activated during a sample period. All segments that were active for more that a specified threshold period are then shown active in the editor canvas. The timing parameters for the displays can be set via the property sheet.

As a result of using the multiplexed display, you should be able to really 'play' with the circuit and watch the visual feedback from the display.

Note that the displays will indicate a short-circuit condition on the microcontroller bus as long as switches are pressed. In the original circuit, series resistors are used between the three switch output lines and the corresponding port B lines to avoid this problem. Unfortunately, it is impossible to model the series resistors using the std_logic_1164 logic system. Either a full analog circuit simulator or an even more complex digital logic system than std_logic_1164 would be required to correctly model such situations.

For a description of the circuit and program, check the previous applet page or click here.