Embedded USB

I'd like to interface a USB mouse to an FPGA. Does anyone have any advice regarding how best to go about doing this. I suspect the use of some form of bridge chip or uC is the way to go but all these seem dominated by the assumption that a PC is involved. Has anyone had any experience in doing this kind of thing please?

TIA,

Rog.

Reply to
Roger
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There are UHCI and presumably EHCI cores for FPGAs. However, it's a

*lot* of space in your FPGA, just to support a mouse. Maybe you want to consider one of the embedded host ICs like the Cypress SL811HS.
Reply to
larwe

Go to your local hamfest/computer swap meet and see if you can find someone who will trade your USB mouse for a serial or PS/2 one.

The difference in complexity of the project will be reduced by a factor of several hundred...

Reply to
cs_posting

...unless your anticipated build volume exceeds one.

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          Michael Kesti            |  "And like, one and one don't make
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Reply to
Michael R. Kesti

Hi, You may be able to use a VNC1L from FTDI (USB host controller). See

formatting link

- Charles

Reply to
charlesoram

Atmel AT90USB1287 is a uC with onboard On-The-Go USB controller. OTG's can be both host and device...

/RaceMouse

Reply to
RaceMouse

You could try using the Maxim 3421E which is driven through an SPI interface. I've used one of these and they are quite straightforward to program (a simple register interface). As others have remarked the FTDI and Cypress chips are alternative possibilities.

Andrew

Reply to
Andrew Jackson

My advice would be: don't try. It may be possible, but it's almost certainly not practical.

Unless that FPGA is really very big, and doing a heck of a lot of things already, the USB implementation would probably end up an order of magnitude bigger than the entire rest of the the project. It takes a rather powerful CPU and a good deal of extra code/builtin libraries to implement USB host-side. Doing that in an FPGA would be like mounting your bed-side alarm-clock on an 18-wheeler in order to move it long distances.

That's because the whole *idea* of USB is that a PC should be involved. The move towards USB can be interpreted as a nifty marketing plan to keep PCs alive and present in households for the foreseeable future.

Reply to
Hans-Bernhard Bröker

I do not know how complex (in matters of FPGA cells) a USB host is, but I think it could be easily placed into one.

I guess you have some kind of soft-core on the FPGA, so you might pull lot of the protocol into software. Also limiting it to USB mouse only might simplify the design.

Anyway, an (fullblown) USB host stack takes about 8K Code on an ColdFire.

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Reply to
42Bastian Schick

Nope. A 180MHz ColdFire can do, and I guess lower speeds would as well.

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42Bastian
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Reply to
42Bastian Schick

ISP1561 from NXP e.g. needs PCI, but AFAIK there are USB host chips with a simple data/adress bus plus chip-select.

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42Bastian
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42Bastian Schick

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