WEBVTT NOTE This file was exported by MacCaption version 7.0.06 to comply with the WebVTT specification dated March 27, 2017. 00:00:00.267 --> 00:00:06.340 align:center line:-1 position:50% size:68% Most of our customers have a huge amount of knowledge working on many different standards, 00:00:06.340 --> 00:00:10.210 align:center line:-1 position:50% size:44% and in all these standards, there's a definition of a test point. 00:00:10.210 --> 00:00:19.453 align:center line:-1 position:50% size:36% For example, you see TP0, TP1, TP2, TP3, TP4, TP3''. 00:00:19.453 --> 00:00:27.928 align:center line:-1 position:50% size:50% All these test points have to do with where in the link the test point is. 00:00:27.928 --> 00:00:33.700 align:center line:-1 position:50% size:60% For example, TP0, TP1, is very often right at the bond wires of silicon, 00:00:33.700 --> 00:00:38.739 align:center line:-1 position:50% size:61% perhaps TP2 is right at the Type-C connector, 00:00:38.739 --> 00:00:45.679 align:center line:-1 position:50% size:50% TP3'' is maybe inside the receiver after equalization and clock recovery, 00:00:45.679 --> 00:00:50.450 align:center line:-1 position:50% size:45% but every standard has a different definition of test points. 00:00:50.450 --> 00:00:55.989 align:center line:-1 position:50% size:42% There's no right or wrong, so customers tend to get stuck. 00:00:55.989 --> 00:00:59.526 align:center line:-1 position:50% size:46% Sometimes they say, "Hey, they changed the test point." 00:00:59.526 --> 00:01:02.829 align:center line:-1 position:50% size:47% There's no right or wrong definition. 00:01:02.829 --> 00:01:09.703 align:center line:-1 position:50% size:53% The key thing is to go to the USB4 spec and read carefully the definition, 00:01:09.703 --> 00:01:13.540 align:center line:-1 position:50% size:36% not the picture of what it is. 00:01:13.540 --> 00:01:15.208 align:center line:-1 position:50% size:21% Two examples. 00:01:15.208 --> 00:01:21.415 align:center line:-1 position:50% size:69% When they moved from the Thunderbolt 3 test point to USB4, 00:01:21.415 --> 00:01:30.490 align:center line:-1 position:50% size:64% they changed not the definition of the test points but they renamed, for example, TP3 EQ to TP3. 00:01:30.490 --> 00:01:33.760 align:center line:-1 position:50% size:33% It's not right or wrong, it's just a different name, 00:01:33.760 --> 00:01:38.332 align:center line:-1 position:50% size:57% but the spec is very clear about where it is. 00:01:38.332 --> 00:01:44.738 align:center line:-1 position:50% size:54% Understanding the definition of test point for USB4 is critical, 00:01:44.738 --> 00:01:50.210 align:center line:-1 position:50% size:45% otherwise the testing will be done at the wrong spot 00:01:50.210 --> 00:01:52.546 align:center line:-1 position:50% size:62% and the margins will be completely inaccurate. 00:01:52.546 --> 00:01:54.348 align:center line:-1 position:50% size:38% That's another huge gotcha. 00:01:54.348 --> 00:01:59.152 align:center line:-1 position:50% size:60% Just this week alone, I probably have three emails from customers 00:01:59.152 --> 00:02:05.959 align:center line:-1 position:50% size:64% who are confused about the test point definition, mainly because it's changed. 00:02:05.959 --> 00:02:10.530 align:center line:-1 position:50% size:61% Sometimes it's because it's not how they understood it from a different technology, 00:02:10.530 --> 00:02:14.067 align:center line:-1 position:50% size:37% but the bottom line is, you've got to look at a spec, 00:02:14.067 --> 00:02:17.037 align:center line:-1 position:50% size:56% and you've got to understand how USB4-- 00:02:17.037 --> 00:02:20.607 align:center line:-1 position:50% size:55% not Thunderbolt 3, not USB 3.2, not PCI-- 00:02:20.607 --> 00:02:24.144 align:center line:-1 position:50% size:50% it's how USB4 defines the test points. 00:02:24.144 --> 00:02:29.783 align:center line:-1 position:50% size:56% That's another gotcha that gets customers into lots of issues. 00:02:29.783 --> 00:02:32.719 align:center line:-1 position:50% size:37% It sounds like the gotcha is, someone sees TP3 00:02:32.719 --> 00:02:35.255 align:center line:-1 position:50% size:43% and they just assume they know what that means for their spec, 00:02:35.255 --> 00:02:42.095 align:center line:-1 position:50% size:57% but because it's different from spec to spec and even from 3.2 to 4.0, for example, 00:02:42.095 --> 00:02:47.200 align:center line:-1 position:50% size:60% people are getting confused or thrown off, and they need to go back and read the spec. 00:02:47.200 --> 00:02:48.535 align:center line:-1 position:50% size:30% That's exactly correct. 00:02:48.535 --> 00:02:55.242 align:center line:-1 position:50% size:51% In fact, if you look at the USB4 spec, and I'm looking at a picture over here, 00:02:55.242 --> 00:02:59.946 align:center line:-1 position:50% size:48% and if you see where they draw TP3 in the USB4 spec, 00:02:59.946 --> 00:03:09.389 align:center line:-1 position:50% size:43% it looks from the picture like TP4 00:03:09.389 --> 00:03:19.866 align:center line:-1 position:50% size:63% is where the test point that includes the clock recovery and receiver equalization is. 00:03:19.866 --> 00:03:26.139 align:center line:-1 position:50% size:60% That's what it looks like in the diagram, but if you look at the definition, that's not correct. 00:03:26.139 --> 00:03:34.014 align:center line:-1 position:50% size:65% Even the picture in the USB4 spec could be confusing, but the wording is very clear. 00:03:34.014 --> 00:03:44.357 align:center line:-1 position:50% size:61% It says that TP3 is measured at the receptacle side, and it applies the reference equalizer. 00:03:44.357 --> 00:03:49.963 align:center line:-1 position:50% size:51% Even within the same spec, you have to not just look at the picture 00:03:49.963 --> 00:03:54.668 align:center line:-1 position:50% size:50% and assume, "Hey, TP4 is right where the receiver equalization should be," 00:03:54.668 --> 00:03:58.138 align:center line:-1 position:50% size:38% you need to read the words. 00:03:58.138 --> 00:04:02.642 align:center line:-1 position:50% size:68% That's where some of the confusion can come from 00:04:02.642 --> 00:04:07.080 align:center line:-1 position:50% size:44% if you're not being super rigorous with some of these definitions. 00:04:07.080 --> 00:04:09.049 align:center line:-1 position:50% size:24% Okay, interesting. 00:04:09.049 --> 00:04:12.052 align:center line:-1 position:50% size:26% Is that spec public? 00:04:12.052 --> 00:04:14.921 align:center line:-1 position:50% size:27% Yes, it absolutely is. 00:04:14.921 --> 00:04:22.963 align:center line:-1 position:50% size:52% Thunderbolt 3 was and continues to be an Intel proprietary spec, 00:04:22.963 --> 00:04:28.201 align:center line:-1 position:50% size:45% so most folks do not have access to the Thunderbolt 3 spec, 00:04:28.201 --> 00:04:31.705 align:center line:-1 position:50% size:42% but the USB-IF is very different. 00:04:31.705 --> 00:04:37.644 align:center line:-1 position:50% size:38% If you just Google "USB.org" or "USB-IF USB4 spec," 00:04:37.644 --> 00:04:42.149 align:center line:-1 position:50% size:49% anybody in the world has full access to the USB4 spec.