USB transceiver for FPGA

The FTDI 245BM sounds like what you want (although it's only 1.1).

See..

..for details.

I've a board based on this I built for my own use (see under downloads on my web site). I've a couple sitting here that someone said they wanted but money hasn't been forthcoming.

Yours for £30 each if you want one/both for prototyping.

See my downloads page for details of an example project showing how to drive it, it's relatively easy.

Nial Stewart

------------------------------------------------ Nial Stewart Developments Ltd FPGA and High Speed Digital Design

I'm working on a project with USB to a XILINX FPGA. The interface chip I'm going with is Phillips ISP-1501

Good Luck, Colin

I have looked at that one some time ago but there was a message on the Philips website that the chip is going obsolete and that scared me away... I tried to confirm with the Philips rep. here in Ottawa,Canada but all I got to talk to was an answering machine!. Did you manage to get an eval board for it?

Thanks for the suggestion, it looks like they also have USB 2.0 chip, the board you have looks interesting too. I will search a bit more before deciding.

Their chip will not run USB2.0 high speed, only full speed. ( I have been able to get 1 MB/sec max on a real board ) Otherwise it is great, I have used it on several boards. They are going to have a high speed chip but it is at least a year off as it is just in planning , this is a major bummer for my projects.

Have you looked at the USB 1.1 and 2.0 IP Cores at

I looked very closely at the 1.1 version and found it took only 6 pins and $1.75 transceiver chip.

Ken

there is a japanese design (VHDL, and Visual basic host example) that uses no tranceiver at all, ie USB DM,DP directly to FPGa

antti

Is it free? :)

That is very interesting and that is what I went looking for. I imagined the logic in the FPGA would wiggle D+ and D- appropriately. I understand that the 480Mbps of 2.0 might be tough in a garden variety FPGA, but 1.1 might be doable.

I wonder if the special LVDS pins of a Cyclone or Stratix would do 2.0? Of course going to Stratix would negate any BOM savings.

Ken

and

Of

its free but I cant give yout the url, tried to find it again for you but failed, searching on japanese sites is a bit difficult :)

it is from some-one who wrote it for XSP-009 board, but there are no links to it from XSP-009 official site(s) as much as I see.

I have the files, can send you per email if you wish, let me know antti

I've thought about that, two pins programmed for 3V3-cmos should be good for tx and rx of SE0 but I never got around to checking if one of the differential standards on the FPGA would be within spec for USB?

-Lasse

google usb.lzh =>

:) found! antti

It has been awhile since I looked at the USB spec, but I seem to recall that there is a non-standard state that is used to signal the rate or some other aspect of the interface. I want to say this state is both signals high or both low at the same time. Am I out to lunch on this?

If there is a non-standard state on these pins, you would not be able to use an LVDS driver. You would need two independant outputs.

I did a quick & dirty project based on the OpenCores USB 1.1 design and drove the D+ and D- pins straight from the FPGA. I wasn't concerned about strict compliance to the USB spec...

I got the project to work fine, but I only tried it on a couple of computers. Different USB hosts might complain about the direct D+ D- interface.

I did have to do some mods to the OpenCore USB design. As I looked though it I found some things I was not real happy with. There was no problem meeting timing with the Xilinx Spartan-2 chip I used.

John Providenza

John Providenza wrote: : I did a quick & dirty project based on the OpenCores USB 1.1 : design and drove the D+ and D- pins straight from the FPGA. : I wasn't concerned about strict compliance to the USB spec...

: I got the project to work fine, but I only tried it on a couple : of computers. Different USB hosts might complain about the : direct D+ D- interface.

: I did have to do some mods to the OpenCore USB design. As I looked : though it I found some things I was not real happy with. There was : no problem meeting timing with the Xilinx Spartan-2 chip I used.

Do you plan to conmtribute the mods back? It would be appreciated...

Bye

John Providenza wrote: : I did a quick & dirty project based on the OpenCores USB 1.1 : design and drove the D+ and D- pins straight from the FPGA. : I wasn't concerned about strict compliance to the USB spec...

: I got the project to work fine, but I only tried it on a couple : of computers. Different USB hosts might complain about the : direct D+ D- interface.

: I did have to do some mods to the OpenCore USB design. As I looked : though it I found some things I was not real happy with. There was : no problem meeting timing with the Xilinx Spartan-2 chip I used.

Do you plan to contribute the mods back? It would be appreciated...

Bye

John,

That's pretty cool. I might try it some day after I get some more experience under my belt.

My problem was that I needed an fpga IP solution at an OTS price and reliability, but all I found were extremes. Either the core was "free" and not guaranteed fully compiant or the price was sky high. So I wound up sticking with my old reliable NetChip @ $8.

Ken

imagined

understand

Of

pins

single ended zero (SE0) is both both pins low and afair you have to both detect and generate that, my idea was to use two standard cmos IO's for that and wire a diffential set in parallel.

-Lasse