Linux-ready, open-platform ARM9/DSP SBC costs $89
linuxfordevices.com
linuxfordevices.com
Everytime I see a laptop or netbook with a modem port or an ethernet port I cry a little.
Another silly question (I am a SW developer not HW) but, can the display port be universally replaced by an USB3 port?
Why yes or why not. Feel free to call me names, I rather take it and learn than surf the waves of ignorance.
Industrial, hobby and embedded control are usually a generation or two behind 'mainstream' when it comes to io, also there is usually a need to interface to older devices.
So, yes, board manufacturing would be easier but it would be harder to sell the boards, because those are exactly the markets that these boards are targeted at. They're not 'mainstream' devices, or at least, not until they've been packaged as some kind of appliance.
> Everytime I see a laptop or netbook with a modem port or an ethernet port I cry a little.
An ethernet port ? Those are pretty useful, not all connections to the internet for laptops are using wireless, for instance, many companies will not allow the use of WI-FI on their premises for security reasons, so wiring the laptops is the only option there.
> Another silly question (I am a SW developer not HW) but, can the display port be universally replaced by an USB3 port?
Not yet, but that may happen at some point in the future.
There are a number of competing solutions for the permanent replacement of the display connectors with something more bus like, USB is only one of those.
This will change over time, already there are monitors that will connect to USB besides the more conventional standards, such as the samsung 940ux.
I hear USB is very CPU heavy, anyways.
In regard to USB3 specifically, it's plenty fast, but it has the major distinction versus Ethernet that it's not bus-addressable, i.e. it has no provisions for network routing. Also, I suspect (but I'm not certain) that its latency is relatively high compared to something like DisplayPort.
When you've finished prototyping and have your own board you can drop their daughter board and buy just the core for 69 euros.
Pretty sweet (and they are good guys also).
The OMAP-L138 Processor only supports usb 1.1 and usb 2.0. In general, a fair number of low power processors in the PDA/netbook realm only support usb 1.1. It may be possible to use an external usb 3.0 controller but that would dramatically complicate your board design.
There are a lot of applications where wifi is not a better solution than ethernet. I work on robotics and wifi doesn't make sense. We are pushing a lot of data around in near real time and the SBCs are permanently mounted close together. Why use wifi there? We see better performance (network and power consumption wise) and simpler setup with ethernet. We usually will have a half dozen SBCs on a switch and then in some cases a wifi access point that is optional. When we are debugging in the field we turn on the AP and stream data back to a tablet or netbook to observe, but otherwise it is off.
The other problem with not having connectors on the board is dongle and price creep. If I have 6 SBCs, and each one needs some kind of networking adapter external to it, all of sudden my nice neat solution is a mess of wires. And the price jumps from $89 to $139, multiplied by however many I am using.
from http://www.usb.org/about/faq/ans5 :
Q2: Why can't I use a cable longer than 3 or 5m? A2: USB's electrical design doesn't allow it. When USB was designed, a decision was made to handle the propagation of electromagnetic fields on USB data lines in a way that limited the maximum length of a USB cable to something in the range of 4m. This method has a number of advantages and, since USB is intended for a desktop environment, the range limitations were deemed acceptable. If you're familiar with transmission line theory and want more detail on this topic, take a look at the USB signals section of the developers FAQ.
Q3: How far away from a PC can I put a USB device? A3: With the maximum of 5 hubs connected with 5m cables and a 5m cable going to your full speed device, this will give you 30m of cable (see section 7.1.19 for details). With a low speed device, you will be able to get a range up to 27m, depending on how long the device's cable is. With a straightforward cable route, you will probably be able to reach out 25m or so from the PC.
Take a look at your mackbook on the side, the two biggest holes are for the modem and ethernet ports. Time to downsize them, not to get rid of them.
So, how difficult is it for manufacturers to get together and join efforts to find solutions for the benefit of all? wait, I have to stop daydreaming about utopia again.
PS.
What I meant again, if you can plug a mouse, printer, camera, mic, etc into a usb port, why not a monitor, ethernet or any other rogue device? I want answers like 'displays use flux-capacitors u dumbass' or 'ethernet uses quantum waves u fucktard therefore blah blah' or is it just manufacturers being dickheads?
USB was meant to be universal.
As was PL/I, to use a software example.
Seriously though, USB just doesn't have the right features for certain applications. Not enough bandwidth for good graphics, for one.
Finally, there's the issue of size. Yes, you could have a board with a bunch of USB ports and Ethernet adapters, etc. hanging off that. But you get a smaller device if you integrate your peripherals. On this board the video controller is in the OMAP chip, along with an Ethernet MAC. The board itself is just bringing these out to a physical interface.
We are at a point where throwing more transistors onto a chip and making a built-in Ethernet module is much, much cheaper than manufacturing an extra board and putting it together.
Ethernet is designed for low-ish latency, moderate bandwidth, and long distances. It does not have enough bandwidth to replace HDMI, and Ethernet routing and addressing is not well-suited to the problems solved by USB. My own testing has shown that 802.11g will not often exceed ~15mbit/s, even with a device sitting right next to the access point. All devices on a wireless network have to share the same 54mbit/s with each other and with any other noise that happens to interfere. Switched Ethernet gives the full bandwidth to all devices, all the time.
HDMI and DVI are designed for direct, zero-latency, high-bandwidth links over medium distances. The current iteration of HDMI specifies a bit rate of 10.2 gigabits per second, over distances up to ~50 feet. It's a one-way interface (for now). Since it's mostly unidirectional, and doesn't have any kind of routing, it could not replace USB. If you added USB-like bus features, it would likely not be fast enough for displays.
USB is designed with a simple master/slave hierarchical bus topology, which is ideal for desktop peripherals. Even USB3 at 5gbit/s isn't enough to replace HDMI, and that 5gbit/s is used for control as well as data, and shared across all devices on a particular interface. Plus, USB cannot exceed 15 feet without repeaters.
USB is also not well-suited to replace PCI(e) for graphics adapters, because PCI(e) allows for very-low-latency communication, DMA, etc.
That's a really nice board, now to find an excuse to get one :)
Another really cool (tiny!) looking device is the Ubiquiti Ministation, but unfortunately it doesn't have USB and therefore isn't a choice for this project.
For when you need more power, there are a lot of cool options such as the BeagleBoard and GuruPlug http://www.globalscaletechnologies.com/t-guruplugdetails.asp...
Curious, how did you find out about them?
Incidentally, LinuxJournal has quite a few advertisers with small Linux boards.
Has anyone found a good source for suitable screens for these small boards? I am not talking about USB2 based displays(which tend to be quite pricey), but precisely screens using more specific ports(DVI-D on Beagle) and VGA here on Hawk.
That is, I am looking for a screen suitable for putting in enclosure with the board.