Crafting a Simple Digital Counter with the EPF10K10LC84-3N FPGA
In the realm of DIY electronics, FPGAs (Field-Programmable Gate Arrays) offer remarkable flexibility and functionality. The EPF10K10LC84-3N, part of the Altera (now Intel) FLEX 10K series, is a great choice for experimenting with digital logic. This FPGA provides a good balance of resources and performance for implementing custom digital circuits. In this article, we’ll explore how to use the EPF10K10LC84-3N to build a simple digital counter. This project is perfect for gaining hands-on experience with FPGA programming and digital logic design.

Understanding the EPF10K10LC84-3N FPGA
The EPF10K10LC84-3N is a mid-range FPGA with 10,000 logic elements, making it suitable for a variety of digital applications. It operates with a maximum clock frequency of 100 MHz and features a range of I/O options. Its programmable nature allows for the implementation of custom logic circuits, ideal for educational and experimental projects. This FPGA’s moderate size and complexity make it a practical choice for building a digital counter.

Materials Needed
EPF10K10LC84-3N FPGA
7-segment displays (2 pieces for displaying count)
74HC595 shift registers (2 pieces)
16 MHz crystal oscillator
10kΩ resistors
Push-button switches (for reset and increment)
100Ω resistors
Capacitors (10µF, 100nF)
Breadboard and jumper wires
5V DC power supply
FPGA development board (if available)
JTAG programmer
Circuit Design and Assembly
Design the Digital Counter Circuit: The goal is to create a binary counter that displays the count on two 7-segment displays. The EPF10K10LC84-3N FPGA will handle the counting logic and control the displays via 74HC595 shift registers.

Clock Signal Generation: Use a 16 MHz crystal oscillator to provide a clock signal to the FPGA. This clock will be divided down to create a slower frequency suitable for counting and displaying.

7-Segment Display Control: The FPGA will interface with the 74HC595 shift registers, which will drive the 7-segment displays. Connect the serial data output of one shift register to the serial data input of the next. This setup allows the FPGA to control both displays using only three I/O pins: data, clock, and latch.

Push-Button Switches: Integrate push-button switches for resetting and incrementing the counter. Connect these switches to input pins on the FPGA. Debounce logic will be implemented within the FPGA to ensure clean, reliable input readings.

Assemble the Circuit: Place the components on a breadboard according to the design. Connect the 16 MHz crystal oscillator to the FPGA’s clock input. Wire the 74HC595 shift registers to the FPGA, ensuring connections for data, clock, and latch signals. Connect the 7-segment displays to the outputs of the shift registers. Set up the push-button switches and connect them to the FPGA’s input pins.

Programming the FPGA: Using FPGA design software (e.g., Quartus II), create a design that includes:

A clock divider to generate a slower clock signal from the 16 MHz input.
A binary counter to increment and count in binary.
Logic to control the 74HC595 shift registers and drive the 7-segment displays.
Debouncing logic for the push-button switches.
Compile the design and upload it to the FPGA using a JTAG programmer.

Testing the Counter: Power the circuit with a 5V DC supply. The 7-segment displays should show the count value. Press the increment button to advance the count and the reset button to clear the count. Verify that the count increments correctly and that the displays update as expected.

Fine-Tuning: Adjust the FPGA design as needed to improve the counter’s performance or add features such as a count limit or additional display digits. Experiment with different display multiplexing techniques to optimize the design.

Conclusion
Building a digital counter with the EPF10K10LC84-3N FPGA is an excellent way to explore FPGA programming and digital logic design. By interfacing with 7-segment displays and shift registers, you gain practical experience in creating custom digital circuits. This project not only enhances your understanding of FPGA capabilities but also provides a solid foundation for more complex digital designs. Whether you’re a beginner or an experienced hobbyist, working with the EPF10K10LC84-3N offers valuable insights into the world of programmable logic and digital electronics.