Project Overview
This project had us create a digital circuit that displays the count from 00 to 80. The two output displays must be common cathode seven-segment displays. The two displays require a multiplexed design. The ones-unit display is controlled by an asynchronous counter designed with a 74LS93 MSI counter IC. The PLD mode equivalent of the 74LS93 is the CNTR_4BIN_AS. The tens-unit display is controlled by an asynchronous counter designed with SSI logic gates. Need to Hold the count once it reaches 80.
There were many differences in the design mode (Right) and PLD mode (Left). Instead of the displays on the design mode, there are the multiplexxed design on the PLD mode, then there is also no switches on the PLD mode, they are replaced by pins that can then be connected to switches on a breadboard. Input connectors are used to control what goes into the circuit and the output connectors are basically what the circuit puts out. the uploading process is quite easy, you just connect the chip via USB and then you transfer the PLD circuit over to it, and then with proper wiring you can have a working circuit on the breadboard.
Bill of materials
Wires: 13
MyDAQ board: 1
Chip: 1
Very simple with the chip being able to do everything a full blown circuit can.
MyDAQ board: 1
Chip: 1
Very simple with the chip being able to do everything a full blown circuit can.
Conclusion
SSI circuits are much larger and more difficult to handle because of all the gates, MSI is much easier to handle and gets the job done just as well. takes one component to do the job of many. the limitations of the MSI circutit is that you cannot set a different low, it will always be 0. The ripple effect is an a situation that occurs when creating an asynchronous circuit. There is a slight delay within the circuit, since it is not synchronized to the clock creating a ripple. In my design I have my ones-place circuit driving the tens-place circuit, counting 1-9 and reading 10 and resetting back to 0. but when the tens-place circuit reads the 10 on the ones-place circuit it counts up 1. This happens untill the tens-place reaches an 8, and it is wired to pause the entire circuit, stopping the tens-place circuit at 8 and the ones-place at 0 creating the number 80. My classmates had the same general design, the way in which things were connected could be slightly different but the general setup of the presets, resets and pauses were all the same.