[MUSIC] Good morning. In this video, we will continue explaining the functionality of the VerilUOC_Desktop tools. We already know how Logisim and VerilCirc work and now we will see how the other tools BoolMin and VerilChart operate. Let's begin with BoolMin. BoolMin is a verification tool that will be used in those exercises whose answer is a boolean expression. As we have learn with Logisim and VerilCirc, our explanation will rely on a specific Coursera exercise. The exercise 2.3.a. This exercise asks to minimize the Boolean expression that appears on the screen. The first thing we should do is to minimize the Boolean expression on the paper, and then enter the obtained expression into BoolMin to check if your answer is right. To open BoolMin, we go to Simulate, Verification, and click on the BoolMin tab. At list of Coursera exercises requiring a BoolMin is displayed. Click on 2.3.a. You can see that this strange expression appears. This is the same expressions we had in the problem statement, but written in a different language. Here you can see both expressions: Differences arise from the symbols used to express the Boolean operations. In BoolMin, the exclamation sign (!) is used to represent the NOT-operator, the inverter. The ampersand (&) is used to represent the AND, and the plus sign (+) is used to represent the OR-operator. The Boolean expression you have obtained as the solution of the problem. should be entered into the box located in the lower part of the BoolMin window, using the exclamation sign for NOT, the ampersand for AND, and the plus for OR. Let's write it. Now we should save the file. Remember that the filename must not contain any space. The extension.bm will be automatically added. And finally, click the Verify button in the lower part of the Verification window. BoolMin tells me that unfortunately the answer to the problem is wrong, and provides an example of a combination of values for a, b, c, d, and e for which my formula and the expression in the problem statement generate different values. In this case, my formula generates a 0, while the expression in the problem statement generates a logical 1. As in the case of a VerilCirc, BoolMin provides a four uppercase letter code that, if entered in Coursera answer box will inform that the solution is wrong. What specifically BoolMin is telling me is that the expression entered is not equivalent to the original one, so I should check my calculations to detect where the fault is. At this point, the VerilUOC_Desktop wiki may help us. Let me open the wiki to show you. Look for the BooIMin section in the wiki. And see how the last point is entitle "Clues to identify errors when the entered expression and the initial one are not equivalent". Click on it. This page gives you hints to detect the fault. Well, I have checked my calculations. I have detected the error and I have computed what I believe is the right answer to the problem. In this example, see how now the variable "a" has been replaced by an inverted_a. Now, I enter the new expression into BoolMin, save the file, and click on Verify. In this case BoolMin tells me that my expression is certainly equivalent to the one in the problem statement, but that further simplification is possible. The expression entered is not considered the right one, however, I am closer to the solution. See that the four letter code is new. If entered in the exercise answer box, this code will inform me that my expression is equivalent to the proposed one, however, further simplification is required. I should analyze again my results to see how to simplify further the Boolean expression, enter the new expression into BoolMin, save the file, and verify it. Remember that, at the end, you must introduce the four letter code corresponding to the best solution you have obtained into the Coursera answer box. OK? So, let's go to the last VerilUOC_Desktop tool, VerilChart. VerilChart is a verification tool that you'll use in those exercises whose answer is a time-chart or chronogram. As in the previous case, our explanations will rely on a specific exercise; in this case, exercise 5.2.a. This exercise asks to generate the output waveforms q0, q1, and Y of this circuit. Let's assume I've solved the exercise on the paper, and they believe that the time-chart that you are seeing in this screen properly reflects the behavior of the circuit. Once again, I should enter this time-chart into VerilChart to check if I am right. To open VerilChart, go to Simulate, Verify. and click on the VerilChart tab. At list of Coursera exercises requiring VerilChart is displayed. Click on 5.2.a. In the right side of VerilChart window appears a waveform editing panel with the waveforms defined in the exercise. At the bottom of this panel you will find the buttons that will allow you drawing or erasing the waveforms. With the left button of the mouse press on the panel left-most button and begin to draw the waveforms by introducing horizontal and vertical lines. If you make an error while drawing the waveforms, well, don't worry: Click on the Erase button, select the area you want to delete, and draw it again. Let me complete the rest of the waveforms. Well, once introduced all the waveforms, save the file, remember that the filename cannot contain any white-space, and finally, in order to check the chart, mark the boxes "by transition" and "by output" in the "Option of Verification" area, and click on Verify. Well, what a surprise! I was wrong again. VerilChart shows me which signal is wrong and when. See in this case, that the fault happens between t2 and t3 in the q0 signal. Now I should recheck my time-chart. Anyway observe how easy it is to introduce the waveforms in VerilChart. Here concludes the introductory videos about the VerilUOC_Desktop tools. I hope that they have been useful for you and I hope you won't have many problems when using these tools in the weekly assignments. Please remember to enter the four letter code into the answer box of the Coursera exercise; if you don't, Coursera will assume that you didn't answer the question. In case of doubts, you can consult the wiki and/or consult the FAQ document. These FAQs collect the most frequent problems reported by students in earlier editions of the course so, it's possible that your question is already answered in the FAQs. If despite all this you still haven’t solved your problem, enter a question in the forums dedicated to the VerilUOC_Desktop tools and there it will be answered either by another colleague who had the same problem and managed to fix it, or by a member of the staff. We strongly urge you to enter your questions about the use of any particular VerilUOC_Desktop tool in the proper forum. You can see that there are three forums dedicated to these tools, one for Logisim and VerilCirc, one for BoolMin and one for VerilChart. For example, if a question or trouble arises while you are working with Logisim or VerilCirc, what you have to do is go to the forum "Logisim and VerilCirc", open a new thread and enter your question. As a summary, the main rule is ... Please use only these forums to introduce questions about VerilUOC_Desktop; do not use any other forums of the course, OK? And well, that's all. It's time to work on the exercises. Good luck for everybody.
