One Protocol to Rule Them All!? – #34

The USB Type-C brings a lot of protocols into one physical connector, but is there room for one protocol to handle all our IO needs? Mike Hoffman and Daniel Bogdanoff sit down with high speed digital communications expert Jit Lim to find out.

USB Type-C brings a lot of protocols into one physical connector, but is there room for one protocol to handle all our IO needs? Mike Hoffman and Daniel Bogdanoff sit down with high speed digital communications expert Jit Lim to find out.

 

0:00 This is Jit’s 3rd podcast of the series

1:00 We already have one connector to rule them all with USB Type-C, but it’s just a connector. Will we ever have one specification to rule them all?

2:00 Prior to USB Type-C, each protocol required it’s own connector. With USB TYpe-C, you can run multiple protocols over the same physical connector

3:00 This would make everything more simple for engineers, they would only need to test and characterize one technology.

3:30 Jit proposes a “Type-C I/O”

4:00 Thunderbolt already allows displayport to tunnel through it

4:30 Thunderbolt already has a combination of capabilities. It has a display mode – you can buy a Thunderbolt display. This means you can run data and display using the same technology

6:30 There’s a notion of a muxed signals

7:00 The PHY speed is the most important. Thunderbolt is running 20 Gb/s

7:15 What would the physical connection look like? Will the existing USB Type-C interface work? Currently we already see 80 Gb/s ports (4 lanes) in existing consumer PCs

9:20 Daniel hates charging his phone without fast charging

9:40 The USB protocol is for data transfer, but is there going to be a future USB dispaly protocol? There are already some audio and video modes in current USB, like a PC headset

11:30 Why are we changing? The vision is to plug it in and have it “just work”

12:00 Today, standards groups are quite separate. They each have their own ecosystems that they are comfortable in. So, this is a big challenge for getting to a single spec

13:15 Performance capabilities, like cable loss, is also a concern and challenge

14:00 For a tech like this were to exist, will the groups have to merge? Or, will someone just come out with a spec that obsoletes all of the others?

15:30 Everyone has a cable hoard. Daniel’s is a drawer, Mike’s is a shoebox

16:30 You still have to be aware of the USB Type-C cables that you buy. There’s room for improvement

17:30 Mike wants a world of only USB Type-C connectors and 3.5mm headphone jacks

18:30 From a test and measurement perspective, it’s very attractive to have a single protocol. You’d only have to test at one rate, one time

19:30 Stupid questions

The Huge Challenge of Testing USB 3.2 – #33

USB 3.2 doubles the data rate of previous USB specs, but makes the testing process significantly harder. Find out why in this electrical engineering podcast.

USB 3.2 testing is darn hard! We talk compliance test specs, USB 3.2 testing BKMs, and pre-spec silicon. Guest Jit Lim sits down with Mike Hoffman and Daniel Bogdanoff to talk about the new difficulties engineers are facing as they develop USB 3.2 silicon.

 

Agenda:

In the last electrical engineering podcast, we talked about how USB 3.2 runs in x2 mode (“by two”)

This means there’s a lot of crosstalk. The USB Type C connector is great, but its small size and fast edges means crosstalk is a serious concern.

When we test USB, we want to emulate real-world communications. This means you have to check, connect, and capture signals from four lanes.

For testing Thunderbolt you always have to do this, too.

Early silicon creators and early adopters are already creating IP and chips for a spec that isn’t released yet.

2:00 They’re testing based on the BKM (Best Known Method)

3:30 Jit was just at Keysight World Japan, where many people presented BKMs for current technologies. Waiting for a test spec to be released is not an excuse for starting to work on a technology.

4:50 How many companies are actually developing USB 3.2 products? The answer isn’t straightforward – the ecosystem is very complex and there are multiple vendors for a single system (like a cable).

6:30 Many USB silicon vendors will develop an end-product and get it certified to prove that their silicon will work. They then sell the silicon and IP to other companies for use in their products.

7:50 Daniel listened to an interesting podcast about how Monoprice reverse engineers complex products and sells them for cheaper:
https://www.npr.org/sections/money/2014/11/28/366793693/episode-586-how-stuff-gets-cheaper

9:40 There are some BNC cables at the Keysight Colorado Springs site that were literally wire pulled and built in the building.

10:00 Has anything changed as USB technology advances? There are a lot of new challenges – multiple challenges, retimers, multiple test modes

Testing retimers is nontrivial, they are full receivers and full transmitter.

11:30 When a new spec is developed, what does that look like? How far does the test group go when setting a new spec?

The spec doesn’t look at how to test, it just looks it what it should do.

Then, there’s a compliance test specification (CTS). This is developed by a test group, that looks at how things should be tested.

So, there are two groups. the first asks “what should the spec be?” and the second asks “how do we test that group?”

13:30 How many people are testing USB 3.2? Even though the compliance test specification is not developed yet? There are non being shipped, but there is a lot of activity!

14:30 What are the main challenges? Basics. When you have 10 Gbps over copper on a PCB, people are failing spec! There are issues with some devices passing only intermittently. Especially over long cables and traces.

15:45 Cheap PCBs make things even more tricky. So, there’s very sophisticated transmitter equalization and even moire sophisticated receiver equalization. It’s crucial to keep the low cost PCB material and processes to keep the overall end-product cost low. Using higher end materials would dramatically increase the cost of consumer products.

17:30 The first TV Mike bought was after his internship at Intel. He bought a $30-ish 1080i TV for $1600. Now, you couldn’t give away that TV.

18:30 Stupid questions for Jit:
What is your favorite national park and why?
What is your favorite PCB material and why?

 

 

 

 

USB 3.2 + Why You Only Have USB Ports On One Side of Your Laptop – #32

USB 3.2 DOUBLES the data transfer capabilities of previous USB specifications, and could mean the end of having USB ports on just one side of your computer. Find out more in today’s electrical engineering podcast with Jit Lim, Daniel Bogdanoff, and Mike Hoffman.

USB 3.2 DOUBLES the data transfer capabilities of previous USB specifications, and could mean the end of having USB ports on just one side of your computer. Find out more in today’s electrical engineering podcast with Jit Lim, Daniel Bogdanoff, and Mike Hoffman.

 

1:00
Jit is the USB and Thunderbolt lead for Keysight.

1:30
USB 3.2 specifications were released Fall 2017 and released two main capabilities.

USB 3.2 doubles the performance of  USB 3.1. You can now run 10Gb/s x2. It uses both sides of the CC connector.

In the x2 mode, both sides of the connectors are used instead of just one.

4:00
The other new part of USB 3.2 is that it adds the ability to have the USB silicon farther away from the port. It achieves this using retimers, which makes up for the lossy transmission channel.

5:00
Why laptops only have USB ports on one side! The USB silicon has to be close to the connector.

6:30
If the silicon is 5 or 6 inches away from the connector, it will fail the compliance tests. That’s why we need retimers.

7:15
USB is very good at maintaining backwards compatibility

The USB 3.0 spec and the USB 3.1 spec no longer exist. It’s only USB 3.2.

The USB 3.2 specification includes the 3.0 and the 3.1 specs as part of them, and acts as a special mode.

9:00
From a protocol layer and a PHY layer, nothing much has changed. It simply adds communication abilities.

9:55
Who is driving the USB spec? There’s a lot of demand! USB Type C is very popular for VR and AR.

12:00
There’s no benefit to using legacy devices with modern USB 3.2 ports.

13:45
There’s a newly released variant of USB Type C that does not have USB 2.0 support. It repurposes the USB 2 pins. It won’t be called USB, but it’ll essentially be the same thing. It’s used for a new headset.

15:20
USB Type C is hugely popular for VR and AR applications. You can send data, video feeds, and power.

17:00
Richie’s Vive has an audio cable, a power cable, and an HDMI cable. The new version, though, has a USB Type-C that handles some of this.

18:00
USB 3.2 will be able to put a retimer on a cable as well. You can put one at each end.

What is a retimer? A retimer is used when a signal traverses a lossy board or transmission line. A retimer acquires the signal, recovers it, and retransmits it.

It’s a type of repeater. Repeaters can be either redrivers or repeaters. A redriver just re-amplifies a signal, including any noise. A retimer does a full data recovery and re-transmission.

21:20
Stupid Questions:
What is your favorite alt mode, and why?
If you could rename Type-C to anything, what would you call it?

 

 

 

USB Type-C – #1

What does USB Type-C mean for the world? Daniel Bogdanoff and Mike Hoffman sit down with Jit Lim to find out. We discuss super fast charging, blazing data transfer – and, of course, things catching fire as a result.

What does USB Type-C mean for the world? Daniel Bogdanoff  and Mike Hoffman sit down with Jit Lim to find out. We discuss super fast charging, blazing data transfer – and, of course, things catching fire as a result.

Video version (YouTube):

What does USB Type-C mean for the world? Daniel Bogdanoff (@Keysight_Daniel) and Mike Hoffman sit down with Jit Lim to find out. We discuss super fast charging, blazing data transfer transfer – and, of course, things catching fire as a result.

Watch the video version and ask us any questions you might have on the Keysight Oscilloscopes YouTube channel or in the comments below!

Look for new episodes each 2nd and 4th Thursday.

Visit Keysight’s USB Type-C design and test solutions page for app notes and more!

Discussion overview:
What is the EEs Talk Tech podcast?
What is USB Type-C, one port to end all others!
Reversible plugs
Show and tell
-Superspeed USB, micro USB
USB Type-C cables are the same on both ends
Host/Device Source/Sink vs role negotiation

USB Power Delivery (USB PD) overview

USB PD for USB A was deprecated

USB Type-C charger has 60 watts of power!

Charge your phone very quickly using USB PD 10:00

5V is an hobby-industry standard level, what about going forwards?

What does USB Type-C look like for day-to-day life?  LED projectors? USB Noodle makers?

Q: Can I find a cheap USB Type-C cable? Should I?

A: Probably over time, but if it’s poorly made it could go badly

Phones are literally blowing up!

The cable isn’t just a wire anymore 14:59

USB alt modes:

USB is the cable to end all cables!

It can handle Displayport, HDMI, VGA, DVI, Thunderbolt, ethernet, power, headphones

MHL device discussion

No headphone jack needed!?!

Is USB Type-C available in stores?

Are manufacturers pushing Type-C or are consumers demanding it?

USB A to C, USB B to C, Thunderbolt to USB C adapters are allowed in the USB C spec (USB Type-C specification)

Make sure to look for USB Certification when you buy products

USB IF mandates that products be certified before being sold

A bad USB Type-C implementation can destroy your stuff!

How are USB alt modes implemented?

What makes up the hardware? 20:20

All USB Type-C cables & hardware have to be the same!

CC (Configuration Channel) line starts the handshake and is a dedicated pin

Make sure cables only have one CC! 21:40

USB Type-C is reversible! 22:20

The device receptacle does the signal routing based on cable position and orientation

How does device negotiation work? For example, what if two phones want to charge each other?

A device can be a host (sinking) or a device (sourcing) 24:20

How does it happen? 24:45

RP, RD, RA resistor network is fundamental to Type-C

What do the resistors mean?

RP means “always a source”
RD means “always a sink”

These resistor networks have certain values that determine current, etc.

You can have USB Type-C without PD, up to 5 Volts  3 Amps
USB Type-C PD lets you go to 20V 5A

We have two USB test fixtures/USB test jig the N7015A and N7016A

Is USB PD available today?
Temperature sensors (or other fail safe mechanisms) are required 28:00

Are USB Type-C cables active or passive?
In general, USB Type-C cables are passive. Active USB Type-C cables will be used for longer cables.

All USB Type-C cables are required to have an e-mark chip to help with power negotiation 29:15

Not all USB Type-C cables can handle 100W
USB Type-C can go up to 80 Gb data transfer using four TX/RX links!

There’s a lot of room to grow for future USB Type-C revisions 32:10

Predictions 30:30

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