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Something like FT245BM for USB 2.0 ? Parallel -> USB with real USB 2.0 bandwidth ?

Started by Martin Maurer March 4, 2004
Hello,

is there a chip, in functionality like a FT245BM for USB 2.0 ?
I found on websites mentioning the FT245BM compatible for USB 2.0,
but i think they don't use USB 2.0, because transfer rate is "only" 1
MByte/s, which looks like high speed USB.

Is there a faster parallel USB chip, which achieves more than 1 MByte / s ?
I think with USB 2.0 there must be at least a factor of 10 to this speed ?

Regards,

        Martin


"Martin Maurer" <capiman@clibb.de> wrote in
news:c26q04$kkf$04$1@news.t-online.com: 

> Hello, > > is there a chip, in functionality like a FT245BM for USB 2.0 ? > I found on websites mentioning the FT245BM compatible for USB 2.0, > but i think they don't use USB 2.0, because transfer rate is "only" 1 > MByte/s, which looks like high speed USB. > > Is there a faster parallel USB chip, which achieves more than 1 MByte > / s ? I think with USB 2.0 there must be at least a factor of 10 to > this speed ? > > Regards, > > Martin > > >
The FT245BM is a USB 2.0 device that can operate at 12 Mb/s (USB full speed). Cypress has a high speed part that is functionally similar called the SX2. Evidently, they have some drivers that are similar to the DLL that FTDI distributes. I am looking into this part for a project, but I don't know very many details yet. - Al Clark Danville Signal Processing, Inc. -------------------------------------------------------------------- Purveyors of Fine DSP Hardware and other Cool Stuff Available at http://www.danvillesignal.com
On Thu, 4 Mar 2004 09:39:28 +0100, Martin Maurer wrote:

>is there a chip, in functionality like a FT245BM for USB 2.0 ? >I found on websites mentioning the FT245BM compatible for USB 2.0, >but i think they don't use USB 2.0, because transfer rate is "only" 1 >MByte/s, which looks like high speed USB.
I think it's referred to as "full speed" - the fastest USB1.1 could go.
>Is there a faster parallel USB chip, which achieves more than 1 MByte / s ?
Cypress and NetChip have working devices apparently, but I haven't used them.
>I think with USB 2.0 there must be at least a factor of 10 to this speed ?
USB 2.0 goes to 450Mbps, or around 50+MB/sec. Be aware that support for high-speed USB 2.0 is somewhat patchy in current OSs. Microsoft have released EHCI drivers for XP, and I understand that drivers for Linux also exist, but that's about it so far as I know. Some links and further info here: http://www.beyondlogic.org/usb/usbhard2.htm -- Max
"Max" <mtj2@btopenworld.com> wrote in message
news:ckge40p2r3hmm1pupd5aq4fthpd5vp1jlb@4ax.com...
> On Thu, 4 Mar 2004 09:39:28 +0100, Martin Maurer wrote: > > >is there a chip, in functionality like a FT245BM for USB 2.0 ? > >I found on websites mentioning the FT245BM compatible for USB 2.0, > >but i think they don't use USB 2.0, because transfer rate is "only" 1 > >MByte/s, which looks like high speed USB. > > I think it's referred to as "full speed" - the fastest USB1.1 could > go. > > >Is there a faster parallel USB chip, which achieves more than 1 MByte / s
?
> > Cypress and NetChip have working devices apparently, but I haven't > used them.
Stay away from Cypress - we've had nothing but hassles with both the devices and the company. NetChip has been great to work with though.
> >I think with USB 2.0 there must be at least a factor of 10 to this speed
?
> > USB 2.0 goes to 450Mbps, or around 50+MB/sec.
Wrong, USB 2.0 High Speed is 480 Mbps. For whatever reason, USB.org has dropped reference to USB 1.1 for the slower devices. All are included in the USB2.0 specification. So, the end user and developer has to read deeper than just the spec number in the reference. USB High Speed is 480- MBps, Full Speed is 12 MBps, low speed is 1.5 Mbps.
> Be aware that support for high-speed USB 2.0 is somewhat patchy in > current OSs. Microsoft have released EHCI drivers for XP, and I > understand that drivers for Linux also exist, but that's about it so > far as I know.
We have high speed USB devices working in VxWorks as well as Win-XP, and Win-2K. There are drivers available for Linux for the NetChip devices as well.
> > Some links and further info here: > http://www.beyondlogic.org/usb/usbhard2.htm > > -- > Max
> The FT245BM is a USB 2.0 device that can operate at 12 Mb/s (USB full > speed).
12 MBit/s was already possible with USB 1.1, for this i don't need USB 2.0 :-( USB 2.0 supports 480 MBit/s, which should give much more than 1 MByte/s...
> Cypress has a high speed part that is functionally similar called the > SX2. Evidently, they have some drivers that are similar to the DLL that > FTDI distributes. I am looking into this part for a project, but I don't > know very many details yet.
I will have a look on this ! Thanks, Martin
Martin Maurer wrote:
> > > The FT245BM is a USB 2.0 device that can operate at 12 Mb/s (USB full > > speed). > > 12 MBit/s was already possible with USB 1.1, for this i don't need USB 2.0 > :-( > USB 2.0 supports 480 MBit/s, which should give much more than 1 MByte/s... > > > Cypress has a high speed part that is functionally similar called the > > SX2. Evidently, they have some drivers that are similar to the DLL that > > FTDI distributes. I am looking into this part for a project, but I don't > > know very many details yet. > > I will have a look on this !
Perhaps someone who designs USB devices can explain this. I have been told by the chip companies that USB 2.0 full speed devices are not the same as USB 1.1 full speed. I have been told that there are operational differences, or enhancements I guess is a better term, that a USB 1.1 full speed device is not automatically a USB 2.0 full speed device. Is that correct? Does USB 2.0 require new features or modes? -- Rick "rickman" Collins rick.collins@XYarius.com Ignore the reply address. To email me use the above address with the XY removed. Arius - A Signal Processing Solutions Company Specializing in DSP and FPGA design URL http://www.arius.com 4 King Ave 301-682-7772 Voice Frederick, MD 21701-3110 301-682-7666 FAX
> Perhaps someone who designs USB devices can explain this. I have been > told by the chip companies that USB 2.0 full speed devices are not the > same as USB 1.1 full speed.
Could it have something to do with the following: 1) USB 1.1 with full speed occupies the line (around 100 %) with 12 MBit / s. 2) When a USB 2.0 device is used with 12 MBit / s (which is also full speed), than only around 12 / 480 is used. Only speculation... Regards, Martin
> > Cypress and NetChip have working devices apparently, but I haven't > > used them. > > Stay away from Cypress - we've had nothing but hassles with both the
devices
> and the company. NetChip has been great to work with though.
I'm just looking for an USB 2.0 high speed peripheral right now, and of course the SX2 was high on the list. I saw Netchip devices, but thought that Cypress "visibility" would have make the FX2/SX2 family reliable for being widely used. Our distributor looks good for Cypress... but what about the devices ? Please, could you share with us your bad experiences ?
"Antonio Pasini" <NOSPAM_pasini.a@tin.it> wrote in message
news:0aM1c.17160$36.589027@news4.tin.it...
> > > Cypress and NetChip have working devices apparently, but I haven't > > > used them. > > > > Stay away from Cypress - we've had nothing but hassles with both the > devices > > and the company. NetChip has been great to work with though. > > I'm just looking for an USB 2.0 high speed peripheral right now, and of > course the SX2 was high on the list. > I saw Netchip devices, but thought that Cypress "visibility" would have
make
> the FX2/SX2 family reliable for being widely used. > > Our distributor looks good for Cypress... but what about the devices ? > > Please, could you share with us your bad experiences ?
Cypress has proven to be significantly less than reliable as a supplier. They have not been responsive to repeated phone calls and emails for support that was agreed to while in the hardware design phase. The SX2 & FX2 do NOT satisfy USB compliance tests for back drive voltage without the addition of obscure hardware & a specific software mechanism. NetChip, on the other hand, actually acted like they wanted our business and valued us as a customer. They were extremely responsive to ALL issues as they came up. Their devices satisfy ALL USB compliance testing without extra design caveats.
"Antonio Pasini" <NOSPAM_pasini.a@tin.it> wrote in message news:<0aM1c.17160$36.589027@news4.tin.it>...

> I'm just looking for an USB 2.0 high speed peripheral right now, and of > course the SX2 was high on the list. > I saw Netchip devices, but thought that Cypress "visibility" would have make > the FX2/SX2 family reliable for being widely used.
In the past, Cypress have had no problem lying to your face: "Yes, we have no intention of obsoleting these parts." That is, until you go into production and actually order the parts, and your distributor says they're going away. Cygnal's 8051-based USB microcontrollers are USB 2.0 full-speed compliant (which means that they only run at 12 Mbps), their development kits are pretty cheap, and the chips have in-system debug capability (gotta love that). I'm going to use one on my next USB project. -a