vivado simulator tutorial

we're now going to start the simulator and demonstrate the basic functionality of using a logic simulator currently the pivotal tool is in the project manager mode and you can see this by the blue bar the top indicating project manager for the four functions I'm going to run the simulator clicking run simulation run behavior simulation and the Vivaro tool then move away from the project manager into the behavioral simulation I can tell them in the behavioral simulation by the blue bar up above in Bovada any time you execute a command with the GUI there's also a corresponding tickle command that you can execute on the command line I can start the simulator as I did with the GUI buttons or I can run a command that's shown here called scrolling up launch simulation the graphical user interface for privado is now different on the left the flow navigator is the same but everything else has changed the toolbar at the top has changed to represent the tools available for the behavioral simulation and also the components here in the middle of the user interface in this box I have what's called scopes this describes the various modules that we have within our design that we can examine we currently only have one for functions and this GL BL is the global library we have the objects pane and in this pane we have all of the objects within the selected for functions module these objects include my inputs my outputs and intermediate signals inside this pane I can see the current value in the simulation of these signals and it's logic type we also have the waveform view this view is probably the most important the one we'll spend most the time and I'm resize a little bit so that I can make more room some people will actually close the objects and the scopes view to give more room for viewing in the waveform view we have a set of tools just for the waveform we have a list of signals and signal values and then we also have the waveform area where the waveforms themselves will be drawn you'll notice here that my signals have values the inputs have the values Z Z means high impedance or not yet set and X is unknown later I will be changing these values to provide a more useful result we also have a tickle console in the simulation view just like we did in the project manager will use the tickle console quite a bit in the simulation view we're going to begin by performing a simple run simulation up here at the very top are a number of buttons that used to run this button here is the run for a specific amount of time I've got a 10 nanoseconds when I press this the simulator will run for 10 nanoseconds when I've done that you can see that the corresponding tickle command run 10 nanoseconds as shown and I could cause the same functionality by just typing in run 10 nanoseconds notice here that in the waveform lines have been shown and these lines show the values of the various signals these three blue values represent the Z of my inputs indicating that they have not been set there in between a 0 and a 1 and the red indicate X's or unknown values typically in a simulation when we see blue or red that means there's a problem in our case there's a problem because we have not yet said the inputs of the simulation so I'm going to do that now but before I do that I want to reset the simulation I can reset the simulation to time 0 by pressing this button right up here or correspond like typing in a tickle command restart so before I issue a run I'm going to set the value of each of my inputs to zero so I'm going to left-click a right-click force constant force value zero and notice that the corresponding command has shown but we've got an ADD force command I'll do the same thing for B force it to the value zero and again the command shows up and then for the for C I'm going to type in a tickle command by hand add force I'm going to put the name see I don't have to put the full path of four functions in this case because the top level function is for functions and I'm going to give it its value zero and have it change at zero now seconds I don't have to indicate the - radix hex this is a single bit value and this will be sufficient so at this point I have assigned the values of the three inputs and now I can perform a run I'm going to type in run ten nanoseconds to cause the simulator to run for ten milliseconds notice in this case that when I simulate my output values are green indicating that I had a good run if I want to look at the full that then the top bar I have from the time it's ten nanoseconds and so I want to zoom out all the way and I'm gonna click on this zoom fit button and this gives me the full simulation value notice here that a B and C are 0 and my outputs are 0 0 0 and 1 at this point I've only simulated 1 values for my inputs I'd like to simulate other values as well so I'm going to add another command to change the value of a to 1 and leave the values of B and C the same I'll run for 10 more now seconds zoom out and you'll notice here that from 0 to 10 nanoseconds I have one set of inputs and one set of outputs from 10 to 20 nanoseconds I have a different set of inputs and my outputs have changed and I'll run yet another command I'll add force be 1 0 nanoseconds run for 10 nanoseconds assume fit and here I have 3 sets of values and my circuit is operating as it should when you have a waveform typically like this you'll have lots of signals and lots of signal transitions and it can be difficult to manage it so there's a couple important tools that you should learn first as we said there's the zoom fit and this will zoom all the way out so you can see the entire waveform we can zoom in with a magnifying glass in the plus zoom out with a magnifying glass 0 minus we can also select zoom fit I can select certain transitions with the mouse when the cursor will tell me exactly where this transition occurs I can move the cursor to 0 by pressing this button move the cursor to the end by pressing this button I can select the cursor and then Center the waveform with this button I can also select a signal and move to the next transition to the right with this button move to the next transition to the left with this button and so on sometimes you'll want to zoom into a region of the waveform so if i zoom back out and I want to zoom in here I can left-click and drag with yellow it will zoom in that region of the simulation when you do large simulations it's difficult to manually type in the values of all of your inputs and so we'll write a script or we'll create a file where we add add force commands and run commands to simulate a pattern of inputs so I have created a file called simulation dot tickle in which I will source so it's a source simulation to tickle and it will run a large set of inputs that have already typed in if i zoom out you can see I have tried all values of a B and C all eight possible inputs for a B and C and then I can go and check the values of each of my outputs in each of these conditions sometimes we may not want all the waveforms these signals here are the intermediate signals of my verilock circuit and i can delete them if they have cluttering the waveform by selecting the signals right-click and delete and if I want to add them at a later time I can select the signals here in the object view right-click add two waveform and they can come back when I am done with a simulation I want to exit the simulator I can click the top right button here close okay I will discard any changes to my waveform I don't need to save these and I'm back to the project manager notice that I don't necessarily need to click the top right button and there's a command called closed sim that can be used to close the simulation with this tutorial you should have enough information where you can complete the simulation for this lab

Channel: BYU Digital Lab

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Id: 6CpSlv1se7U

Length: 10min 23sec (623 seconds)

Published: Thu Jan 25 2018