***************** 1 July 2024 Hi Duane and Thom, After I heard about the Single Pair Ethernet (SPE) I went down the rabbit hole to find out as much as possible about it. I would like to have this in the vehicle because we would get rid of our dedicated GBE cables and have more flexibility for future things like TRN running from the MVC. It seems this is still pretty bleeding edge and we have to verify this will actually work for us. It seems the realistic max cable length is 25m (advertised are 40) which is fine for the in-vehicle bus but not enough to make it through one of our tethers (I have some ideas about that though). However, there does not seem to be a big supply of SPE switches around at this point and none I could find was actually what we would want, which is 2 SPE ports for bus-in and bus-out and then 2-4 normal ports for the devices in the sphere. So I think we have to build this ourselves (but someone should have a look if I missed something). There are a few companies offering PHYs for this. The easiest to deal with seems to be this: https://www.ti.com/product/DP83TG720S-Q1 There are even demo board available that I will probably buy 2 of when I get back to do some cable length experiments. However, the issue with these is that they only do 1GB/s and not 100MB/s, which could be an issue (rather have a slow link when the cable gets bad vs. no link). If you want dual speed, the only PHYs I could find are these: Broadcom BCM89883/4 Marvell 88Q2112-A2 Realtek RTL9010AA The problem with all of them is that there is no info available and that I don't know how you even buy the chips. It might be worth requesting a quote from Digikey (which is a Broadcom distributor) to see if they sell us 10 and give us datasheets. For the switch ICs there is also a bit of research to be done. Microchip makes a bunch of different switches but most of them already have PHYs so we can't use them because we need to put in the SPE PHYs. However, to save dev time it would probably be best to find a switch IC that has 2 MAC ports for custom PHYs and then 2-4 ports with PHYs. There are a lot of options with 1 MAC port but we need at least 2. NXP does have a few switch ICs that have only MAC ports, that would be the fallback solution and we would just have to get a few 10/100/1000 normal Ethernet PHYs to connect to the other port. I will talk to each of you directly about this but I just wanted to give some info that might be useful. Thanks Erik 2 July 2024 Hi Duane and Thom, Duane, do you think you have bandwidth for working on this a bit with Thom being able to help out if you get stuck? Here is what I think we should do: 1.) research if there are some switches already available that have at least 2 SPE 1GB ports and 2-4 normal GBE ports (don't be surprised if you can't find anything). If no suitable switch is found we have to make one ourselves. 2.) research parts for SPE switch: - need to find switch IC that is low power and has ideally 2 MAC ports and 2-4 ports that already have a PHY (Microchip does have a few with 1 MAC port, maybe they have one with 2) - if you can't find that, find a switch IC that only has MAC ports (like these: https://www.nxp.com/products/product-selector:PRODUCT-SELECTOR?category=c704_c1494_c1510) - find a suitable SPE PHY, see if we can get that Broadcom part somehow but if not, I think we just go with the TI PHY and maybe in a year or two something better will come out - study the demo boards for the PHY to see how to integrate them. It does look fairly straight forward, important things are: keep traces for MAC lines short, needs controlled impedance, need to be same length - make a schematic and a board I see this as a filler project to work on when there is nothing more important going on. There is no immediate time pressure on this, I just think we should try to gather knowledge about this and hopefully can upgrade the the vehicles with this at some point in the future. Thanks Erik **************************** 2 July 2024 There is Weidmuller ( Single Pair Ethernet Multi-Drop switch with three SPE ports and two RJ-45 ports) who announced a product in Dec 2023. https://www.weidmuller.com/en/solutions/technologies/single_pair_ethernet/index.jsp https://www.youtube.com/watch?v=9kH9iun41rg The SPE alliance product database might help, but does not seem to be comprehensive. https://www.single-pair-ethernet.com/en/spe-product-database I'd also recommending looking at TI or MicroChip to see if they have an eval board I can help after proposals are in. -Thom Maughan ********************************** 13 July 2024 Emailed Digikey re: Broadcom BCM89883/4 Requested info from Marvell re: Marvell 88Q2112-A2 Requested infr from microchip.com re: switch with 1 MAC ports and 2-4 ports with PHY ************************************ 18 July 2024 Requested RTL9010AA datasheet from Sierra IC Inc