9 ms·
10BASE-T1S is the missing Ethernet link for automotive communications
- londons_explore 4y agoI foresee a 10MBit bus quickly not being enough... As soon as you give programmers something capable of TCP/IP, they'll want to send large globs of JSON back every few milliseconds... Now your network link is full.
- throwawaaarrgh 4y agoData, like software, is a gas. It expands to fill its container.
- jrmg 4y agoDon’t worry - they can gzip it and make it something for the CPU people to worry about instead!
- rsync 4y agoI was curious what the physical connector looks like and I found: https://www.panduit.com/content/panduit/na/en/landing-pages/single-pair-ethernet/_jcr_content/par/columncontrol_935706162/par1/image.img.jpg/1619038762324.jpg https://www.panduit.com/content/panduit/na/en/landing-pages/... ... so, a single pair PHY layer and a connector I have not seen before ...
- oakwhiz 4y agoIf you're just experimenting just do everyone a favor and use RJ45 or screw terminals. These special connectors are really expensive and require special crimp tools.
- nine_k 4y agoRJ 9 are still a thing, I suppose. 3.5 mm jacks, like in audio gear, could work too.
- bluGill 4y agoRJ45 needs to die. As does every other connector that was ever used for more than one incompatible thing. USB got it right: build a custom connector for your application so that nobody will ever plug the wring thing in. I don't care what you replace Ethernet RJ45 with, but make it a standard that is only used for Ethernet.
- oakwhiz 4y agoWeird connectors are hard to hack on. You bring up USB but I couldn't think of a worse example. USB got it wrong, it supports so many different things on a single connector that in some situations it can be impossible to determine what will happen when you connect device A to device B with cable C. Now don't get me wrong, it's great for plugging things into your laptop, but the world of cabling is so much bigger than that, and we don't really need to bring in even more BS connectors where they don't belong. At the end of the day it's someone's job to actually run cable, terminate and test it, and attach equipment to it that people are responsible for. You have to remember that the physical cable plant is infrastructure itself whether it's connected to live equipment or not. There's already a big enough problem with people trying to do things like route display cables through buildings, for example - the workaround that I'm seeing a lot is that people are using specialized signal converters that send HDMI/DisplayPort over a pair of Cat5e/Cat6 cables, just so that structured cabling can use normal cabling/networking supplies (i.e. keystone jacks, patch panels, conduit sizes, testing/tools, etc.) without wasting so much time with planning for projectors/displays ahead of time etc. RJ45 is for twisted pair cabling. It's not specifically for Ethernet. 802.3cg only uses 1 pair. If you use the center pair then it works for TIA-568A, TIA-568B, or USOC. It's great for experimenting since everyone already has twisted pair patch cables to play with. Barring that, just give me screws that I can put the wires into so I don't need to think about connectors at all.
- pmontra 4y agoI did HDMI over Ethernet at home. It works with a 19 m long Cat 6 cable plus two 3 m patch cables. Beware of bending the cable too much if it must go inside pipes in the walls.
- 4y ago
- nynyny7 4y agoThere isn't the connector for 10BASE-T1S or other Automotive Ethernet standards such as 100BASE-T1. OEMs (= car manufacturers) will often define their custom connector. E.g., the Ethernet signal might just occupy two pins on an much bigger ECU connector.
- _moof 4y agoYou can run it on whatever you want. Ethernet pairs in a harness with dozens of other wires and MIL-DTL-38999 connectors are pretty standard in aerospace.
- _3u10 4y agoSounds like Token ring
- nynyny7 4y agoNot really. There is no ring, neither physically, nor logically. It's based on CSMA/CD, like the "good old" coaxial cable Ethernet. (Optionally it can use additional methods to avoid collisions, though.)
- deleted 4y ago[deleted]
- Dylan16807 4y agoNo need to go as far as coax. Half duplex twisted pair ethernet has collision detection and only uses one wire pair at a time.
- captainmuon 4y agoOne effect of standards like these is that they are a higher barrier to entry. In a previous job doing embedded development we had some requests from automotive manufacturers but didn't apply for the tenders, because that would have required that we redesign our product. Some parts were bought and that wouldn't have been possible, and for others the upfront investment was too much considering the risk.
- gcbirzan 4y ago> The cable harness used today is one of the three heaviest subsystems in the vehicle (weighing up to 60 kg)3. Traditional Ethernet cables use four differential pairs for data transmission, adding weight and routing complexity, which is not optimal for automotive applications. To address this, new IEEE standards were developed to support Ethernet transmission over single twisted pair cables, which, coupled with the reduced cable harness lengths enabled by zonal architecture, can offer significant cable savings and weight reduction. Because in cars that are at least 1000kg, a few grams definitely matter.
- nynyny7 4y agoYou'd be surprised how much the reduced cable cost matters to an OEM.
- gcbirzan 4y agoYes, I'd be surprised. How much money would reducing the number of pairs in a cable from 4 to 1 save? A few dollars, at most.
- aidenn0 4y agoAutomotive manufacturers will spend 6 figures in NRE costs to save $0.003 in unit costs. If they only redesign every few model years, use the same hardware across several models, and they sell millions of cars per year, the math works out pretty well.
- brk 4y agoSave a few dollars, times 10's of thousands of vehicles in higher production models. I've posted this before in more detail, but the short version is that when I was working at Ford Motor Co in the late 90's I remember seeing some internal documents championing how they saved ~$200 off a production Taurus (at the time a ~$20,000 vehicle) via a bunch of $10 and $20 individual cost savings. It was a big deal, added up to real dollars.
- 4y ago
- m463 4y agoDoes it have Collision Detect? :) more seriously, this is ethernet over a single twisted pair. fascinating. https://en.wikipedia.org/wiki/Ethernet_over_twisted_pair https://en.wikipedia.org/wiki/Ethernet_over_twisted_pair There is another interesting one 10BASE-T1L up to 1km.
- oakwhiz 4y agoIt does! The collision detect signal is repurposed somewhat for PLCA but is in fact working and backwards compatible with 10BASE-T MACs if you ignore the additional functionality. The stations with PLCA will try to avoid collisions with each other but you can barge in and collide with them anyway and it will still work. The main warts in the standard are dynamic PLCA node ID allocation and the fact that PoDL is undefined for non-point-to-point topologies, besides how odd it is to implement SCCP for PoDL. I've been thinking that a way around the PoDL aspect is to ignore SCCP and to just use periodic square wave pulse trains with a certain frequency to indicate to the PSE that it should switch power on. Basically an "I know what I'm doing" indicator to prevent sniffer adapters and unterminated connections from being provided live DC voltage.
- Avlin67 4y agobare in mind the higher latency for 1000BASE-T1 but 10BASE-T1S should nice. Here a wikipedia article https://en.wikipedia.org/wiki/Ethernet_over_twisted_pair https://en.wikipedia.org/wiki/Ethernet_over_twisted_pair
- adrianmonk 4y agoSo it's basically old-school, pre-switch, pre-hub Ethernet. A lot like thinnet. Except with a single twisted pair instead of coaxial. And also, its approach to time-division multiplexing is more like DOCSIS cable modems, where a schedule determines whose turn it is to transmit. So it's going to be cheap and high utilization, and the max latency will be under control, but the min latency might not be wonderful.
- PinguTS 4y agoIt is much more robust on EMI. It is much cheaper, because it uses very thin wires. There are lots of thing, which distinguish it from the good old Coax days with required proper termination of 75 Ohms.
- adrianmonk 4y agoYeah, I'm not trying to minimize it. Rather, I'm just trying to describe what it's conceptually like at a high level. Not requiring termination definitely seems like a good thing. Somehow they're always fiddly.
- edrxty 4y agoDoes anyone know the safety implications of a multi drop bus like this for safety critical systems? Typically if one device fails, it can bring the entire network down, hence why single drop buses have become popular for diverse networks
- oakwhiz 4y agoYou should have a plan for network instability or outages that causes a safety stop for anything affected by that fault domain. If uptime is important then you might have two separate networks side-by-side. You can also split a large fault domain into a few smaller networks. There is also the possibility of being clever with how things are wired so that the PHY can be physically cut out of the bus by a watchdog, but that doesn't help with cable faults and introduces its own possibility for failures. It's also possible to have another set of emergency stop signal wires side by side with the digital communications in case there's an issue.
- dragontamer 4y agoIsn't CANbus a multi-drop bus? Do car companies run safety-critical functionality off of it? -------- My understanding is that 10BASE-T1S is a replacement for CANbus. Whatever CANbus does, 10BASE-T1S should do it better. It happens to be Ethernet (albeit a much slower Ethernet), but Ethernet/IP/TCP is something modern programmers understand better than UARTs / CANbus.
- PinguTS 4y agoActually, CAN XL is just around the corner with up to 20 Mbps vs 10 Mbps of 10BaseT1S. The other difference is that CAN XL has a paylod of 2048 bytes and will have data link layer security from the get go. While 10BaseT1S has just a little bit over 1 kbytes and MACsec is still ery expansive. That said, both technologies are just prototypes and expected availability is in about 3 years.
- eigen 4y ago> That said, both technologies are just prototypes and expected availability is in about 3 years. OnSemi claims to have a production 10Base-T1s MAC-PHY now. https://www.onsemi.com/products/interfaces/ethernet-controllers/ncn26010 https://www.onsemi.com/products/interfaces/ethernet-controll...
- jimmyswimmy 4y agoBeen using one of the Analog demo boards, I think one of the ADIN1100 parts which is 10BASE-T1L instead, to solve a problem that occurred when I let a mechanical engineer order a cable for me. No twisted pair inside. Ethernet on either end. We barely found space inside the pressure vessel for the demo board (project at this point running on fumes, so instead of designing a tiny little board with just the few required parts I bought a pair of these boards), and connected the other one to the other end of a pair of wires in the cable. Astonishingly, not only did it work the first time, it worked well enough to stream video. I'm hoping to see a more standardized PoDL interface crop up so that I can use two wires for data and power combined, for lower-power subsystems. There's a lot of application for this standard, I hope it catches on enough that I can keep buying chips for it for a long time.
- johnwalkr 4y agoAbout 4 years ago I tried to use 10BASE-T1 with PoDL (power over data line) in a robotics project. I gave up after about 18 months of trying to put together the first prototype. I was able to get engineering samples (before they were on the market) of the magnetics and related stuff from Pulse, but I couldn't manage to get a PHY from anyone. The reason I wanted to use it is power consumption. I had previously planned to use 100BASE-T (normal 100Mbps ethernet) in a robotics project but it turns out that it uses about 0.8W per port (1.6W per cable) so it was using by far using more power than my various microcontrollers. Faster ethernet uses even more power. There is a standard for low power ethernet but it's not a huge improvement and you really have to go out of your way to select components to use it. I ended up using CAN, but it will be really nice when these standards become well-supported.
- eigen 4y ago> I'm hoping to see a more standardized PoDL interface crop up so that I can use two wires for data and power combined, for lower-power subsystems IEEE802.3da is working to add PoDL on 10Base-T1. objective 9. Specify optional plug-and-play power distribution over the mixing segment objective 10. PSE shall only energize the mixing segment when at least one PD is connected objective 11. Support addition and removal of a node or set of nodes to a continuously operating powered mixing segment https://www.ieee802.org/3/da/802d3da_objectives.pdf https://www.ieee802.org/3/da/802d3da_objectives.pdf
- kats 4y agoLol this is so biased. And if you look at the costs for ADI's parts, you'll see it's not happening any time soon.
- legulere 4y agoSome low-power low-speed low-cost ethernet would also be very interesting for home automation. Thread/Zigbee just has 250kb/s and that is already enough. Cables offer more reliability and the possibility for low voltage dc power supply.
- nine_k 4y agoI wonder if one could run Ethernet over RS-485 physical layer, pretty ubiquitous and inexpensive.
- mfwit 4y agoThe applications in commercial buildings where there are already miles of single pair communication cabling run is even more interesting. https://buildings.honeywell.com/us/en/products/by-category/building-management/controllers/zone-and-unitary-controllers/honeywell-optimizer-unitary-controller https://buildings.honeywell.com/us/en/products/by-category/b...
- pantalaimon 4y agoYou can use UART, all you need is a CAN PHY which is maybe 50ct as a break out board https://doc.riot-os.org/group__drivers__dose.html https://doc.riot-os.org/group__drivers__dose.html
- throwawaaarrgh 4y agoThere's always Powerline Ethernet
- anonym29 4y agoWhat a horrible cookie consent screen. Using Firefox on Android I get just one option, "accept all", with no option to close or minimize the blocking popup, and no option to accept anything less than all cookies.
- 1letterunixname 4y agoVendor has a hammer to sell, and so finds nails. This has already been evaluated and re-evaluated over the past 10+ years. https://en.wikipedia.org/wiki/SocketCAN https://en.wikipedia.org/wiki/SocketCAN https://en.wikipedia.org/wiki/FlexRay https://en.wikipedia.org/wiki/FlexRay Infotainment is more likely to go with less fault-tolerant, cheaper-to-implement standards, but you can bet critical systems will never.
- exabrial 4y agoMost HNers are probably too young to remember any alternatives to Ethernet like Token Ring, but that’s what it sounds a lot like oddly enough. The only other thing I don’t understand is if each node has the opportunity _not_ to transmit, that seems like it would cause jitter in late and see if he bunch of nudes sometimes transmit and sometimes don’t. Not sure what I’m missing
- aidenn0 4y agoI remember Token Ring and 10BASE2 (I never used 10BASE5). This doesn't sound like it though, it sounds like a traditional Ethernet Bus?
- londons_explore 4y agoI really wish standards were speed agnostic... The standard should be written, and let the devices decide what speed they want to speak. If sender and receiver of a packet both want to speak 1Gbit over the link with clever QAM and adaptive channel coding, then let them do that... And if another device only supports 10kbits with a single mosfet and pull up resistor, then thats fine too... The purpose of the standard should be to define who gets to speak when on the link, and how those speeds should be negotiated, and how devices can fairly share the capacity and be functionally compatible.
- londons_explore 4y agoThe cynic in me says that if standards were written this way, with no upper bound on data rate, symbol rate, bandwidth, frequency use, etc, then standards writers would soon be out of a job. Just like the RS-232 serial standard originally was 300 bps, but now people use functionally the same protocol to talk 9600 bps, 57600 bps, 1000000 bps, 25,000,000 bps, etc... The original RS-232 standards group is long dead, yet the standard keeps going on because people can use the same spec (with a few tweaks along the way) faster and faster for 6 decades!