lif3l355
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Re: Ethernet port?

Sun Jul 31, 2011 7:21 pm

I know this literally doubles the size of the board, but what about having an ethernet port?
I know you can buy them separately, but they also run up to ~50$ a piece.

Or maybe, since you guys are in contact with a manufacturer maybe poll your current interested users and see if they'd buy a usb+ethernet hub from you? The usb hub is a definite essential if anyone wants to buy one of these, but whats the point of having an awesome computer without networking capabilities?

I've just done some research, and this little gadget here is something that you guys might be interested in manufacturing? as an 'add on' sale? maybe?



That retails for about 50$ regularly.


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abishur
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Re: Ethernet port?

Sun Jul 31, 2011 7:28 pm

They are currently planning on release a "model B" of the device which uses a LAN9512 chip. The chip provides an Ethernet port and 2 usb ports. (whereas the "Model A" only provides for a single USB port).

Ideally there won't be a need for a powered USB hub, but you could use a passive one if more ports are necessary. We'll have to see what the R-Pi team decides on power wise there.
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lif3l355
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Re: Ethernet port?

Mon Aug 01, 2011 1:36 am

Awesome, I can't believe I forgot that I read that. It's going to be 5-10$ more, but definitely well worth it. Hopefully the new model doesn't affect the cost of production/manufacture.

Des_Zac
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Re: Ethernet port?

Thu Aug 04, 2011 2:54 am

Regardless, I'm buying multiples of both! This is finally my chance to start building the things I've wanted to for years but the computers I have are too big!

Svartalf
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Re: Ethernet port?

Thu Aug 04, 2011 10:10 pm

Quote from abishur on July 31, 2011, 20:28
Ideally there won't be a need for a powered USB hub, but you could use a passive one if more ports are necessary. We'll have to see what the R-Pi team decides on power wise there.

Careful there. Peak current allowed by the 2.0 spec is 500ma with non compliant devices supporting up to 1A. A passive one's nifty for handling things like mice, keyboards, etc. but it can't really source more than the maximum available on the port- which means 500ma total, including the juice for the hub itself. For things that need current (There's a few devices, like external HD's, that come to mind there...), you're really, really going to want to have a powered hub unless they're going to source 1A out each of the two ports on the B-model.

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abishur
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Re: Ethernet port?

Thu Aug 04, 2011 11:11 pm

That's I said ideally ;)
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duese
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Re: Ethernet port?

Sat Aug 06, 2011 3:09 pm

Are there really two USB-Ports on modell B?
I thought there is just one on each.

Michael
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Re: Ethernet port?

Sat Aug 06, 2011 4:30 pm

Yes, there are two on the Model-B. The CPU provides one USB 2.0 port which is brought directly out to a connector on the Model-A, or feeds the LAN9512 peripheral IC on the Model-B. The LAN9512 then provides one Ethernet and two USB 2.0 ports.

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Lob0426
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Re: Ethernet port?

Sun Aug 07, 2011 7:39 pm

So the ethernet runs through the USB off of the CPU? It thens breaks out into an ethernet and two USB's. So the ethernet is technically half duplex?
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abishur
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Re: Ethernet port?

Mon Aug 08, 2011 1:45 am

It's more like there's a main usb hub, then attached to that hub is a USB to Ethernet adapter also attached to that hub is another hub with 1 to 4 ports (or in the R-pi's case 2 ports).

Also according to this tech sheet it features full-duplex (which if you consider it to be a standard usb to ethernet adapter makes sense)
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WelshMullet
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Re: Ethernet port?

Thu Oct 06, 2011 2:50 pm

http://www.ebay.co.uk/itm/USB-.....19c969515a
One of these and a usb hub? :3

obarthelemy
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Re: Ethernet port?

Thu Oct 06, 2011 4:51 pm

@abishur: USB2 is half-duplex though, so the network adapter part of the 9512 being full-duplex only pushes the issue back up a step.
Sources: "In previous USB versions (i.e., 1.x or 2.0), all communication is half-duplex and directionally controlled by the host." (http://en.wikipedia.org/wiki/U.....B2#USB_2.0)

@WelshMullet: just make sure there's support for ARM Ubuntu, "Ubuntu" by itself usually means x86, not ARM.

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Lob0426
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Re: Ethernet port?

Fri Oct 07, 2011 1:48 am

The LAN9512 plays a game to get full duplex. The Ethernet is connected as if it is two devices not one. Not really full duplex. I am sure some other Ethernet dongles also use this trick. Performance should be ok.

The host port from the BCM2835 is USB 2.0 and therefor half duplex, which then goes into the LAN9512 chip.
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nullstring
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Re: Ethernet port?

Sat Oct 08, 2011 11:13 pm

is USB 2.0 the highest speed bus available on the BCM2835?

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liz
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Re: Ethernet port?

Sun Oct 09, 2011 3:16 am

Sorta kinda. We have a 2-lane MIPI CSI-2 and a 2-lane MIPI DSI interface, each rated at a max speed of 1 gigabit per lane. It might be useful for point-to-point links, but we're almost certainly not going to be supporting it as a standard feature. That said, if you can hack it, we can bring it!
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Lob0426
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Re: Ethernet port?

Thu Oct 13, 2011 12:45 am

The MIPI's are an interface for video. 1Gbps per lane equals 125 MB/s or 500MB/s for all four lanes (250 up and 250 down?). Now if I could just find a chip that would let me use that for a disk interface! Or an Ethernet interface! Will not actually get that kind of performance but it would be a third path for data.
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Re: Ethernet port?

Thu Oct 13, 2011 1:28 am

Do I understand Lob0426 and Liz correctly if I conclude that the B board will have two half duplex 1 Gb/s channels for USB/LAN? LAN will take up max. 2x100 Mb/s (full duplex). That's a powertrain around here.

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abishur
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Re: Ethernet port?

Thu Oct 13, 2011 3:51 am

@kme - nope sorry ;) The 4 gigabit lanes Liz is refering to is through the mipi DSI and mipi CSI (2 lanes per interface). Lobo is saying it would be awesome if he *could* find a device that would let him connect a disk or ethernet interface to these lines to get some faster than usb 2.0 speed going on. There actually is a device over on sparkfun.com that lets you hook up an ethernet port to a DSI interface, but if you read the information on it you discover that it's actually pretty slow.

The USB port is a standard USB 2.0 port with standard max speeds. The official LAN9512 manual states that the full duplex ethernet port shares the USB bus with the 2 USB ports attached to the hub. But that's still plenty of speeds for 10/100 Mbps ethernet. I actually have done data transfer tests using a usb to ethernet adapter for 100 Mbps and even transferring/receiving lots of data (full duplex situation) the difference between my built in ethernet port and the usb to ethernet adapter was extremely negligible (under a couple seconds difference)
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eicristian
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Re: Ethernet port?

Thu Oct 13, 2011 10:00 am

Quote from lif3l355 on July 31, 2011, 20:21
I know this literally doubles the size of the board, but what about having an ethernet port?
I know you can buy them separately, but they also run up to ~50$ a piece.

Or maybe, since you guys are in contact with a manufacturer maybe poll your current interested users and see if they'd buy a usb+ethernet hub from you? The usb hub is a definite essential if anyone wants to buy one of these, but whats the point of having an awesome computer without networking capabilities?

I've just done some research, and this little gadget here is something that you guys might be interested in manufacturing? as an 'add on' sale? maybe?



That retails for about 50$ regularly.
you don't need one of those usb hub things the Raspberry Pi already has one ethernet and two usb ports, i think that's enough to work with :D and if you will need to plug a usb flash drive you could always use the usb hub

kme
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Re: Ethernet port?

Thu Oct 13, 2011 10:55 am

you don't need one of those usb hub things the Raspberry Pi already has one ethernet and two usb ports, i think that's enough to work with :D and if you will need to plug a usb flash drive you could always use the usb hub
Add to this that you could "just" swap the LAN9512 chip on raspi B with a LAN9514 (one LAN, four USB) and I doubt very much it will drive costs up by more than a $ or two. However this will need a new board and the raspi guys will line up to kill me just for suggesting this :-) The A and B boards are a done deal featurewise, so let's see them first. But the alphabet doesn't end with B...

obarthelemy
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Re: Ethernet port?

Thu Oct 13, 2011 12:43 pm

@abishur: watch the CPU usage too.

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Lob0426
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Re: Ethernet port?

Sun Oct 16, 2011 3:23 am

It would be nice to have an SoC that had everything the BCM2835 does plus on chip Ethernet support. This would be a really good tablet SoC. The BCM router chips have wireless with a processor and four Ethernet ports and USB 2.0 built into the SoC. So it is perfectly possible. I also saw a Videocore III with 10/100 built into it.

Maybe a future tablet multimedia chip will have the Ethernet native to the package.
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abishur
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Re: Ethernet port?

Sun Oct 16, 2011 4:49 am

Quote from kme on October 13, 2011, 11:55
Add to this that you could "just" swap the LAN9512 chip on raspi B with a LAN9514 (one LAN, four USB) and I doubt very much it will drive costs up by more than a $ or two. However this will need a new board and the raspi guys will line up to kill me just for suggesting this :-) The A and B boards are a done deal featurewise, so let's see them first. But the alphabet doesn't end with B...

Actually, we were discussing this in another thread and sadly it's not just as simple of a matter as dropping one chip in place of another. There's the additional cost of the fancier chip, the additional cost of the USB ports, and then, more importantly here, the additional cost of the data lines on the PCB, the increased footprint of the PCB to hold the data lines and extra USB ports, and this further assumes that there's spare space on one of the layers to host the 8 additional lines that would be required to add two additional ports without causing interference with any of the other pre-existing lines.

The r-pi team has put a lot of work into meeting the price limit while providing the maximum amount of features. At this point in the game I seriously doubt there's a such thing as a device whose additional would only cost a $ or two. Now as you said, the alphabet doesn't stop with B and if they rework the next board from the ground up to include different/additional features then I think additional USB ports would be a strong contender based on the feedback provided in the forum.
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