USB device without computer

Hi there, I just need to known if there is possible to use a USB device (flash drive, webcam, keyboard, etc.) with no computer interaction, so I can use it in a specific application with a FPGA ????

Thanks in advance.

Reply to
USB wcam
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You are confused. A USB device will only work when it is talking to a USB host, which pretty much has to be a computer.

But I suspect that when you say "computer" you mean "PC or MAC". There is no _fundamental_ reason that you couldn't implement a USB host on a sufficiently large FPGA. The easiest way would be to use an FPGA with an embedded PowerPC or ARM processor and run an embedded Linux system on it that is big enough to support a USB host. Regardless of how you do it you'll find that implementing a USB host is not the world's lightest- weight systems programming task, in any way, shape or form.

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Reply to
Tim Wescott

Theoretically it is possible to do USB in state-machine-logic, but in practice it is not wise to attempt to handle the higher protocol layers that way.

What you end up doing is using a micro controller (small, embedded computer) either as a discrete chip, in the form of a specialized USB- to-SPI or whatever adapter, or constructed within the fabric of the FPGA itself.

Reply to
cs_posting

Keeping in mind that you're implementing a USB _host_ stack, which is a heck of a lot more work than implementing a USB _client_ stack.

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Reply to
Tim Wescott

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Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

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Reply to
Vladimir Vassilevsky

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Yes. And even most of the device/client stacks are practically going to use a micro controller type of architecture.

I see the link to the usb-to-spi device has been posted in the thread already. This is of course a microcontrollor with the necessary firmware built in.

Reply to
cs_posting

For those devices supported by the Vinculum chip, it is a very easy way to do it. There is a new chip in the works which will support iscochronous transfers, and there will be a development environment to allow users to develop custom apps. Due end of the year-ish.

Failing that, find a microcontroller with a USB host port, or look at the USB host chips available from NXP or Maxim.

NXP have a free host stack for their USB host parts like the LPC2478.

Reply to
Mike Harrison

it.

Unfortunately, this otherwise good chip has one disadvantage: it is very slow. The transfer rates with the flash drive are below 300KB/s. That makes it practically useless for the bulk data transfers.

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

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Reply to
Vladimir Vassilevsky

I just the this chip (exmple: Vinculum VNC1L USB Host Controller) to work with a USB webcam using only frames, I means one data sample (not realtime video) every 30 seconds or 1 minutes, so possibly the transfer rate below

300KB/s is not an issue.

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way to do it.

Reply to
USB wcam

Why the heck embedded linux ? There are embedded USB host stacks (e.g. from HCC Embedded) which run even without an (RT)OS.

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42Bastian
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Reply to
42Bastian Schick

Nowadays people buy & integrate their stacks, not implement them. Implementing USB host would be crazy, unless you think you can do it better than the competition.

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Reply to
Boudewijn Dijkstra

And most of the time that craziness would manifest itself in thinking you can do that.

Reply to
Hans-Bernhard Bröker

Eh -- apparently I'm behind the times.

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Reply to
Tim Wescott

I developed a RTOS. We developed TCP/IP stack. We developed POSIX compliant file system (flash file system on the way). USB host is not quite there yet, but it will be in the near future.

It's not all that hard to do, and it turns out to be actually better=20 then many commercial solutions; and of course there is no comparison to=20 the free opensource trash.

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

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Reply to
Vladimir Vassilevsky

You don't need a 32-bit RISC chip with Linux; a PIC24 can operate as a USB host.

Reply to
Nobody

Can you explain more, This project should work without any computer interaction, so I am surprised about this solution.

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an

Reply to
USB wcam

Either you know something that the experts here do not understand, or it really can not be done.

If you do know something, please share with the rest of us.

don

Reply to
don

What everybody is telling is that you can't do USB host-side without a computer. Your choices are to use a computer makde from off-the-shelf parts/SW or build something custom.

What you're asking is in effect "I want to run a large, complex computer program without any computer." Putting it all into an FPGA isn't going to make it any less a "computer".

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Reply to
Grant Edwards

Perhaps what we have is simply a semantic problem.

The engineers are saying that practically speaking, doing host-side USB requires a computer or a an absurdly more complex bit of dedicated logic. But when we say "computer" we do not necessarily mean something with a keyboard and an LCD flatscreen, which is what the word may mean to users, product managers, whatever.

Instead, what we mean is an essentially fixed hardware engine executing a program. The complexity is in the sequence of instructions rather than in the architecture of the engine itself.

Such "computers" come is all shapes and sizes today, most of which - the ones we call embedded processors - are probably not considered computers by non-engineers.

There are many physically compact solutions to the poster's problem - in fact there are now single-IC solutions because you can now by processors with USB host peripherals and the necessary RAM and ROM stacked on top - used in cell phones for example.

Reply to
cs_posting

What are you refering to ? (Top posting is sometimes bad, isn't it ?)

I have the feeling, you do not have the slightest idea of what you want to do in your project.

Please define: Computer.

Then we might give you more hints.

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42Bastian
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Reply to
42Bastian Schick

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