60 Second Display
For this project, we had to build a circuit that could continuously count from 0 to 60 and restart automatically.
This project was similar to the last one because of the two separate counters that are connected to each other. Once the tens counter reaches a certain number, the ones counter is triggered to restart counting.
Conclusion: Synchronous counters run off of the clock while asynchronous counters rely on another source or the previous counter. The 163 counter is a 4 bit up counter with a pre loadable count start and synchronous load/clear. The 193 counter is a 4 bit up/down counter with a pre loadable start and asynchronous load/clear.
In this project, we had to design a counter that was able to count from 0-60 and restart automatically when the number 60 was reached. We had two counters built that were connected to each other. One counter was built for the tens place and the other was built for the ones place. J/K flip flops were used for the tens place counter and 74LS163 MSI counter for the ones place. There was a reset signal set to work when a 6 was detected in the tens place and when a 0 was detected in the ones place (60). This is a synchronous counter because both of the counters are clocked by an external clock. Once we designed the circuit on MultiSim, we were able to upload the circuit to a CMOD chip on the board. Once we transferred the circuit to the chip and after we wired the board, the hex display attached to the board counted from 0-60 continuously. This circuit is set up with the ones timer connected to the first input clock. Q is connected to the DEC_BCD_7 and notQ is connected to the other clock. The clears and outputs are connected with inverters to make a 6 (110 in binary) since a 60 needs to be shown at the end. For the ones counter, there are ABCD inputs on the 163 counter. Those are all connected to a digital low. The Q's are connected so that a 9 is shown (1001 in binary). The NAND of this counter is connected directly to the clock input of the tens counter. The counter reaches 59 and automatically resets to zero and starts all over again.
Other students built the same circuit with just certain variations.