WEBVTT 00:01.400 --> 00:06.860 Welcome to Lafferty in this video I'm going to show you the complete isolation of the universal shift 00:06.860 --> 00:09.720 register should look like on the base to bored. 00:09.830 --> 00:15.130 Now if you have one or two don't worry on like this and I'm here to help. 00:15.200 --> 00:19.080 I'm more than happy you just send me an e-mail and let me know. 00:19.370 --> 00:22.990 This is probably a little bit more difficult but that's OK. 00:22.990 --> 00:25.130 That's the way I designed it was. 00:25.590 --> 00:26.920 I want to struggle a little bit. 00:26.930 --> 00:30.230 But if you're saying they're spending I don't want you to be frustrated. 00:30.290 --> 00:33.950 I want you to learn and that's the best way of learning is actually doing so. 00:34.070 --> 00:37.980 These labs are designed to have it so you have to understand the code. 00:38.450 --> 00:41.380 If you're ready let's grab your board let's go. 00:41.400 --> 00:41.790 All right. 00:41.790 --> 00:43.260 Here in lab three. 00:43.260 --> 00:47.650 Here is the universal shift register running on my basic toolbar. 00:47.790 --> 00:56.400 Now with the passing of the file that I gave you the inputs that are mapped are you've got an output 00:57.270 --> 01:03.450 which is eight minutes long which is represented by these eight ladies on the front of your base is 01:03.450 --> 01:10.500 two board right here and then you've got your input as your slight input which is these two switches 01:10.590 --> 01:16.500 on the far left over here and you've got your input which is the same as has a shift register in the 01:16.500 --> 01:17.540 previous line. 01:17.550 --> 01:23.520 Is this for switch over here and you've got the clock which is represented by this button right here 01:24.240 --> 01:28.950 and the reset which is indicated by this button over here. 01:28.960 --> 01:35.350 Now the way universal shift register works is very similar to the shift register except that with the 01:35.350 --> 01:40.000 universal shift register you can select if you want to shift to the left or do you want to shift to 01:40.000 --> 01:44.310 the right or do you want to load data and it's like a shift register. 01:44.310 --> 01:47.200 It's the same this or Friendster you just have more options. 01:47.330 --> 01:50.120 So you get demonstration here. 01:50.140 --> 01:55.380 So right here I've got these two select inputs are basically telling my shift register what I wanted 01:55.380 --> 01:57.870 to do right now they're both zero. 01:57.910 --> 02:01.690 So that is indicated as a whole where nothing happens. 02:01.690 --> 02:05.920 So if I click a button there nothing happens to it. 02:05.950 --> 02:14.290 Now if I push them both up right here I'm going to load the data bit and which is represented by just 02:14.290 --> 02:16.420 what's right here which is low right now. 02:16.430 --> 02:21.630 So if I push it you don't see anything because I'm losing zeros seemly now. 02:21.820 --> 02:23.510 Oh I hadn't thought of that up. 02:23.720 --> 02:32.760 And as soon as I was that button there you'll see a data represented by the light so if I push it again. 02:32.930 --> 02:39.230 It's basically a key so there are now five percent down to zero and go to zero in there and it turns 02:39.230 --> 02:40.610 that whole idea off. 02:40.640 --> 02:45.500 So let's go ahead and loaded it a bit and the shift register. 02:45.500 --> 02:45.940 OK. 02:45.950 --> 02:50.550 So when it had low then and now our select here we can determine if you want to shift to the right or 02:50.570 --> 02:51.650 left. 02:51.650 --> 02:53.080 If we shift to the right. 02:53.170 --> 02:56.190 This is basically going to fall off and go away. 02:56.210 --> 02:58.210 So we want to shift it to the left. 02:58.220 --> 03:04.150 So in order to do that we need to have our select before right one down what the far left one up but 03:04.250 --> 03:10.910 push that button you see a shift in over one and every time increase that call button it shifts over. 03:10.910 --> 03:17.430 Now if I'm on a ship at the fairway I go ahead and if I put them both down it's a whole where nothing's 03:17.450 --> 03:20.800 going to happen and push that button that it just stays there. 03:20.900 --> 03:22.400 But I would push them both up. 03:23.390 --> 03:24.250 Then go ahead. 03:24.270 --> 03:28.470 A lot of data that in which you see there lives in. 03:28.720 --> 03:33.610 And now let's say I want to continue shifting them down like so. 03:33.980 --> 03:35.570 OK now I shifting to the right. 03:35.680 --> 03:43.610 I just talked a lot down talk my selection of an old title over an ugly scene there. 03:43.660 --> 03:45.070 If I keep going. 03:45.400 --> 03:49.440 As soon as they get off the edge of your Ellet either that is kind of fall off and go away. 03:49.450 --> 03:54.670 That's because if you look in the code you're actually giving it a zero. 03:54.700 --> 03:58.890 As soon as it shifts out so it goes through and it clears out. 03:58.900 --> 04:06.760 Now here we have a reset which Let's go ahead and load some data and go to hit that target on and then 04:06.760 --> 04:14.750 you got to shift it down to that shifted in there which is a lot more operations but typically you would 04:14.750 --> 04:18.400 have something like inside your FPGA cube. 04:18.470 --> 04:23.010 You would have a clock and other things you'd have control things like that. 04:23.020 --> 04:27.920 And this clock we're just putting all these buttons and it switches so you can actually see and understand 04:28.030 --> 04:29.500 what's going on here. 04:29.510 --> 04:32.880 So give him a reset once again nothing happens. 04:33.050 --> 04:35.890 That's because a reset doesn't occur. 04:36.080 --> 04:37.550 It happens on a clock cycle. 04:37.760 --> 04:43.400 So I have to hold down my reset and press the clock and that's how you clear it which you can see that 04:43.400 --> 04:44.310 in the code. 04:44.380 --> 04:50.370 There's a piece of code there it's a process that is evaluated on a clock cycle. 04:50.370 --> 04:58.550 So for example some more bits in real quick and will explain how what was going on. 04:58.800 --> 05:02.330 OK so I've got three bits here and I clear them. 05:02.490 --> 05:09.540 If I hit the reset nothing's going to happen because that block of code there there's no the clock cycle 05:09.540 --> 05:12.840 hasn't happened yet so it's not being evaluated in that process. 05:12.840 --> 05:18.160 So if I want that to clear out the hold the reset down which is a logical one. 05:18.180 --> 05:22.890 So you see in code it says on the rising edge of clocks says I push this on the rising as the clock 05:22.890 --> 05:28.180 is going to evaluate that process and what that process does is always these values is zero. 05:28.200 --> 05:32.700 So the process is evaluated and your all your Ltds are clear. 05:32.760 --> 05:39.400 Now if you're not getting this on your board and you are lost or are struggling don't worry. 05:39.600 --> 05:46.470 I have a solutions manual on there that you can look at you know go through and explain how step by 05:46.470 --> 05:52.040 step how to get this to simulate Mollison and how to get it to run on this board.