“Actual PWM duty cycle on 7-segment LED display, driven by hardware (PL) and controlled by software (PS).
This project was created for the MiniZed Motor Control Build Challenge and the final application was built on the Mini But Mighty project by Adam Taylor. This project is a VHDL reference design for creating a multiplexed 7-segment display hardware driver in programmable logic, and shows how to to use and test HDL hardware modules on small boards (such as MiniZed) without numerous buttons/switches and LEDs. The example presents the implementation of the created VHDL hardware module into Mini But Mighty project for displaying actual PWM duty cycle on 7-segment display.
For the needs of this project, I created a hand made PCB for the 5641AS quad digit 7-segment LED display. The segments line are connected to header through 300 ohms resistors, the common cathodes of each display are driven by 2N7000 N-MOS transistors whose gates are connected to header by 10 k ohm resistors and grounded by 220 k ohm resistors. A 13-pin header (8 segments, 4 common cathodes, 1 GND) is connected to the MiniZed via an Arduino connector.”