Project Overview
The goal of this project was to be able to create a sixty second timer that would automatically restart using an asynchronous counter and J/K flip flops.
Multisim Circuit
This project was similar in some ways to the deli counter project we had completed because they both used asynchronous counters, and had to connected both chips to a seven segment display. The differences between this project and the deli counter is that in the previous project we only used asynchronous counters however in the sixty second counter, we used a synchronous counter ('163) that had to be connected differently since it held different properties then a asynchronous counter.
Final project Conclusion
The difference between asynchronous circuit and a synchronous circuit is that asynchronous circuits have a ripple effect, meaning that the signal sent to the display is delayed. The other difference is asynchronous counter can only count up staring from zero. Synchronous counters aren't affected by this ripple affect, however they do require more logic gates to function. Synchronous counters are also simultaneously clocked by the same clock, making them faster then asynchronous. There are two different types of synchronous counters including '163 and '193. In this project we used a 4 bit '163 synchronous counter which shows the number being detected on the display, and it is only able to count up. The '193 synchronous counter however also has a 4 bit counter but this one can go up and down. The '193 also counts just like the asynchronous counter in which it will load the number below what is being detected on the circuit.
I started creating my sixty second timer, by reviewing past assignments and the rubric so that I could get a general idea of what I was supposed to create, and what my constraints were. I created my circuit on design mode starting off with creating the 0-6 display with J/K logic gates. To create this I connected the inputs of my 74LS10 chip to clock, meaning it would start at 0, then connecting my outputs so that I would detect a 6 telling my circuit to display a 5. Then I began connecting my '163 chip, by connecting A, B, C and D to ground telling the circuit it would start at 0. Then because we used a synchronous counter, I could connect my output wires so that the number being detected would be displayed. I connected the clock of J/K circuit to the input of my 74LS20 chip so that whenever the ‘163 ship reached a 9 it would tell the J/K circuit to change. However, with my circuit the J/K would change when the ‘163 was at 9, but I needed it to change when it reached zero, so to fix this problem I added an inverter in-between the input of my 74LS20 chip and the clock of the J/K flip flop so that it would change whenever it reached zero. Then to connect my switch to my circuit I used an AND gate to connect the inputs of the 74LS10 and 74LS20 chip to the outputs of the AND gate. Then I connected the input of the AND gate to the clears of my J/K flip flops, and the switch. I figured this out by referring to an old assignment completed in class, which gave me a general idea of what to do. However, this switch only reset my J/K flip flops so to reset them both I connected the clear of the ‘163 chip to the output of the AND gate making it possible for the switch to reset both displays. Some differences between my design and my classmates design is that some of my classmates built there’s in PLD mode while I built it in design mode. Other than that I’m not sure what other design differences my classmates had, but there definitely was some differences since his circuit could be built in many different ways.
I started creating my sixty second timer, by reviewing past assignments and the rubric so that I could get a general idea of what I was supposed to create, and what my constraints were. I created my circuit on design mode starting off with creating the 0-6 display with J/K logic gates. To create this I connected the inputs of my 74LS10 chip to clock, meaning it would start at 0, then connecting my outputs so that I would detect a 6 telling my circuit to display a 5. Then I began connecting my '163 chip, by connecting A, B, C and D to ground telling the circuit it would start at 0. Then because we used a synchronous counter, I could connect my output wires so that the number being detected would be displayed. I connected the clock of J/K circuit to the input of my 74LS20 chip so that whenever the ‘163 ship reached a 9 it would tell the J/K circuit to change. However, with my circuit the J/K would change when the ‘163 was at 9, but I needed it to change when it reached zero, so to fix this problem I added an inverter in-between the input of my 74LS20 chip and the clock of the J/K flip flop so that it would change whenever it reached zero. Then to connect my switch to my circuit I used an AND gate to connect the inputs of the 74LS10 and 74LS20 chip to the outputs of the AND gate. Then I connected the input of the AND gate to the clears of my J/K flip flops, and the switch. I figured this out by referring to an old assignment completed in class, which gave me a general idea of what to do. However, this switch only reset my J/K flip flops so to reset them both I connected the clear of the ‘163 chip to the output of the AND gate making it possible for the switch to reset both displays. Some differences between my design and my classmates design is that some of my classmates built there’s in PLD mode while I built it in design mode. Other than that I’m not sure what other design differences my classmates had, but there definitely was some differences since his circuit could be built in many different ways.