I just read a bit about USB 3.1 and the type C connector. Sounds pretty impressive, at least in the future when more of the capabilities will be fully exploited. I am wondering if there will be plans to incorporate this into the rPi chipset so that we have an even simpler device to power, boot and connect I/O?
It really looks like it might be possible to have say, six USB 3.1, type C connectors on an embedded board like the rPi and be able to connect to a power supply, boot drive, monitor, keyboard, mouse and still have an available port left over using just one type of connector! Pretty cool, huh? Provide 8 ports and use an Ethernet adapter to talk to those obsolete devices you've got sitting around and have two ports spare.
I've never been that enthused about using PC type buses for embedded devices, but with the level of integration available today and the new USB interface, I can't see any reason not to leave the old stuff behind and go with the flow on this one. I see an rPi being just two chips (SoC and memory) with power support.
Not going to happen. At least for quite some time. It would need a completely new SoC design, rather than the minor redesign that was made for the Pi 2.
It would also need significantly more expensive silicon. 8xUSB3 changes the equation from "$25 SBC" to "something with PCIe-bus equivalent bandwidth for peripherals". I'd just be happy with a redesign that moved the ethernet PHY and the storage devices off the USB hub.
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I don't follow this. If every part of the I/O were inside the SoC, why would that be more expensive? Don't you think the internal busses of a
700 MHz processor can keep up with a 5 Gbps serial bus? 32 * 700 MHz is
22.4 GHz. Regardless, only the video has to run at particularly high rates. The rest of the peripherals are relatively low average rates with high burst rates. An SoC is only limited by it's memory band width. Why would the SoC be any more expensive?
I don't think the SoC used in the rPi 2 was done *for* the rPi 2. I think the chip was done for other purposes and used *in* the rPi 2. Am I wrong about this?
I can't imagine that Broadcom is not already designing an SoC chip with USB 3.1 as we speak.
Switching to the Synopsys USB 3.0 or 3.1 IP will cost substantially more in licensing fees than the USB 2 IP which is a mature product
The USB 3 IP may be targeting a smaller process (22, 28nm?). The PHY is substantially different.
The above assumes SuperSpeed (5Gbps) or SuperSpeed+ (10Gbps). It's possible to do USB 3.0 or 3.1 at only 480Mbps, which is just other spec changes.
Doing 480Mbps/USB 2 over Type C is an option. But you still need to route the video into the type C connector: that's an extra chip unless an SoC respin is on the cards.
USB 3 burns more power than USB 2. Most new phones are still USB 2 for instance.
To do type C power requires a redesign of the power system - whether ports are 'pushing' or 'pulling' power, and how much to handle of the power delivery spec (up to 20V 5A). You can choose to not do that: be a 5V 'puller' only and it's simple, but if you're being a hub it's more complex.
Can you substantiate this? I couldn't find anything indicating this. Why do you say "Synopsys USB"? Surely they aren't the only provider of USB IP.
Other than the PHY, IP typically doesn't target a process. Even if it does, a smaller process is usually less expensive for the chip. That's why they continue to shrink the feature size.
What extra chip? Video and USB all come from the SoC, why wouldn't it be routed inside the SoC?
Just like the USB before it, 3.1 is fully backward compatible. The only real power hog is the high speed when using it. If you don't need it, use the slower speeds. If you have use for it, voila, it's there!
Yeah, the power distribution of the rPi is poorly thought out. With USB
3.1 you can do away with the power connector and simplify the power distribution. Very likely a chip will be available to handle all aspects of power for small designs like the rPi. So the current maze of power components will be reduced to a small handful with one IC for a very low price.
Bottom line is USB 3.1 with the type C connector is a *big* improvement with little or no extra cost for small apps like the rPi.
The Pi uses the Synopsys Designware USB 2.0 HS OTG core (dwc_usb_2_0_hs_otg). I've worked on drivers for it. I don't know how much the licensing fees are (and if I did know I couldn't tell you) but USB 2 is mature, USB 3.0/SS is mainstream and USB 3.1/SS+/Type C is bleeding edge. Typically mature products are cheaper than new models.
Changing IP vendor involes changing IP ecosystem, tool setup, verification solutions, licensing setup and contracts. You don't do that without a good reason. Mix and match of IP cores is possible, but life is a lot simpler and less risky buying from one vendor.
On-chip USB is all about the PHY: it's possible to have an external PIPE PHY chip but you don't want to do that for cost, pin count, board cost and space reasons. The rest of the controller is synthesisable logic which, as you say, is less process dependent.
The Synopsys DesignWare USB-C/USB 3.1 PHY IP webpage mentions it targets USB-C 3.1 SS/SSP PHY, Type-C - TSMC 16FF+LL, North/South Poly Orientation which is TSMC 16nm FinFET. There is no public information on what other processes they support.
formatting link
The DesignWare USB-C/USB 3.0 PHY IP documentation page:
formatting link
has a long list of processes including 16nm, 28nm, 40nm, 55nm, 65nm from the likes of TSMC, GlobalFoundries, UMC and SMIC. So that looks like a much more portable target BUT only the TSMC 16nm FinFET supports Type C.
None of the Synopsys USB IP cores mention video - I'm unclear how much PHY support it needs.
/If/ you respin the chip, it's all inside the SoC /but/ you need a respin ($million) /and/ you need a USB type C PHY that supports video ($lots, exact amount not public)
/or/ you don't respin the SoC but you need an external chip (unit cost ~$5 or whatever)
'A chip' = $x added to the BOM. Care to suggest a chip that supports USB
3.1 power delivery so we can see what the pricing looks like?
Changing the connector is cheap, but some of the other things you suggest aren't. The Pi cost envelope is already tight. How much extra on the ticket price would people be prepared to pay?
Fine, but you miss the point that USB 3.1 *will* be incorporated in new designs. This is not a rPi issue, it is a Broadcom issue and *will* happen. The market will use these new CPU chips and they will be competing in a market with the older chips. I can't see the inclusion of USB 3.1 will significantly impact the price of the Broadcom CPU chips other than potentially for the first 6 months while there is a scarcity in the market of USB 3.1 solutions.
You seem to be saying a lack of information implies negative information.
I have no idea why you think there won't be new SoC devices with USB
3.0. It's not a question of "respinning" an old chip. They are constantly designing new chips. The CPU used in the rPi 2 is not the same as the chip in the other rPis. It was not a "respin", it was a new design, as will be any chip with USB 3.1.
No, *a chip* could replace the existing power support *chips*. I believe there are at least two and it may be three. When a popular device requires multiple power supplies it is very common for chip makers to provide a power solution specifically matched to that device. For example, there are any number of multiple rail PSU chips designed specifically to power FPGAs. Same is true for many DSP applications. I expect there would be such a device for a new rPi if the designers wanted it to happen.
How much extra will it cost? I think you are stressing this more than it is worth. Just as other improvements have lowered the cost, I expect a new design which considers the large market for the rPi and other apps can be lower cost as well.
I, for one, have absolutely no use for USB 3.1/C at present. I haven't even got as far as USB 3.0 except for a couple of 2.0/3.0 HDDs!
I am happy with the USB capabilities on /all/ the various machines I have here thankyou - and I don't need even more varieties of USB lead than I have already!
fruit
PS. I haven't got a BluRay drive either, one of yesteryear's 'must haves' ISTR ;)
Actually, the cable thing is one of the big advantages. One cable to replace them all!
Yeah, you will have another cable short term, but in a few years there will be a lot less need for anything else. I read about a Mac with just USB type C connectors and a head phone jack. Not even a separate power jack.
I remember having a similar conversation about USB vs. Firewire back when USB 2.0 was new. The argument was that USB 2.0 didn't offer anything that Firewire didn't, except that there would be one less type of connector on computers. I don't recall the last time I saw a device with a Firewire connector. USB 3.1 type C connector replaces three types of connectors with one. I think it is just a matter of time and not a lot of that.
That's a little negative considering the USB micro connector spec is from 2007. I remember I got my first phone with micro-USB in 2008, also a bluetooth headset with micro-USB at the same time. While I don't use that phone any more, the headset is fine and the chargers of both devices are also fine and other micro-USB chargers work just fine with all my micro-USB stuff (except for the Raspberry Pi but then that's just a bad design.) So I've enjoyed a standard connector for seven years.
Of course, the micro-USB did absolutely nothing for my other stuff using various other USB connectors. USB 3.0 actually introduced some new ones which apparently didn't get that common and of course old gear with the square type-Bs or mini-USB connectors isn't going anywhere.
In that sense, while the type C is great and all, it's just another connector on a long list of USB connectors. I hope it catches on but we'll see. Right very little is available. That Apple laptop and maybe a few Chinese phones. I'd want to add a front panel to my PC with both type-C and old USB connectors and an express card for my laptop but I haven't seen either available. Didn't check right now though.
But Isn't there some converter cable for power? I'm making a rPi laptop and i'm thinking on selling it on eBay and getting lattePuppy. I know, there is usb 2.0 to usb 3.0, but that won't change speeds, only change what type of device it supports. I am thinking a way to make a life hack with paper clips and stuff to Type-C Power
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