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Digital_Lab_03

"Stopwatch"

Choon B. Kim, Ph.D., a retired ASIC engineer

1. Design Specifications:

You design a stopwatch with following features.

1.1) The stopwatch starts by SW[0] = 1 with LEDR[0] = ON, stops by SW[0] = 0 with LEDR[0] = OFF.

1.2) The number of seconds elapsed is displayed on 7-segment display HEX3-HEX0 in 4-digit decimal number.

1.3) The reset operation is done by SW[1] = 1 (reset).

1.4) LEDR[6] blinks at the start time and at the time each second passes.

2. Testing(video on YouTube):

Test case:

The stopwatch stops after 14 seconds passed since the start, and resets to 0.

3. Recommended additional work:

Add the pause function to your stopwatch design as follows.

- The pause function is controlled by KEY[3] which works as a Push-ON Push-OFF button(i.e., the first pressing for ON, the second pressing for OFF).

- A green LED light turns ON in order to show the pause state.

4. Key lesson(s) learned from this Lab:

How to handle the real-time control process operation(s) in digital system design.

5. Timing(optional):

Assuming your design is used as a part of a bigger clock-based system, find the maximum clock frequency of your design.

Explain how you get it.

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