Input Characteristics Determine Debounce Time
After much reading and some calculations, I learnt that theoretically the ideal bits of the LFSR counter in my design should result in the range of 300 µs to 5 ms debounce time. The width had to be quite large since the FPGA board clock speed was 100 MHz. For validation of the specific time to be put in the design, I tested the push button with a range of LFSR widths. I started with low widths that gives about 0.3 ms. When the widths of the LFSR counter was increased till it hit around 25 (more than 50 ms), the push button respond time starts to lag to the human eye. This means the counter took the time longer than it should to determine a stable state. I concluded to just fix it to a value of 0.3 ms debounce time. This way, the glitch input was filtered enough while still look instantaneous to the user.
I continued to make other modules that needed a debouncer such as the touch sensor. Based on its input characteristic, the debounce time as the push button is sufficient for the touch sensor as well. Dr. Shawn taught me that the small microphone needed a different time of debounce since it involves the frequency it would detect. I was then testing variable widths on the small microphone like I did previously with the push button. I found that there were widths that cause my clap not to be detected and at the end I decided to make it debounce for 40 μs as it detects the range of frequencies required while still filtering out the noise.
Towards the end of the week, I was assigned a new task by Dr. Shawn to research on the best wireless interface on a plug that is available in the market. The project was quite interesting involving the control of an operation such as a laundry service that can be made from far with wireless technology. Research mode is now on. Hope I can find something with a good deal while finishing other modules that are not done yet. Dr. Shawn gave me us some tips on the skill of representing graphs that I find very useful for me. He also brought us for the annual tradition of breaking the fast last Friday. We had a great time together as the night was amusing with fruitful talks.