On Sun, 5 Mar 2006 13:37:16 +1100, "Arthur Richards"
<fake@address.com.au> wrote:
>We want to use a Cypress FX2 to send 2 MBytes/sec data to a PC via usb. In
>order to avoid writing a PC driver I'm considering using HID interrupt
>transfers. Latency should be better than 100ms say.
>
>Can anyone see any problems with this?
>
>Thanks,
>Arthur Richards
>
There are several issues here. One is you will have to provide a full
speed configuration that cannot meet 2mbytes per second, all high
speed devices must fall back, even if they don't do anything, so the
user can be told about the problem.
Another is HID. It is not restricted to a particular bus speed; it is
a higher level protocol. However, it is a horrible, complicated
protocol. I would recommend using some bulk protocol, where you can
find an existing winxp driver.
The final is using interrupt transfers. You can do what you want, by
specifying how many transfers per microframe. You must not NAK if you
are trying to send more than one packet per microframe. You can also
transfer up to 1024 bytes per transfer.
Good Luck, Steve
There is no "x" in my email address.
----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----
Reply by nappy●March 5, 20062006-03-05
"Arthur Richards" <fake@address.com.au> wrote in message
news:dufsrb$m9j$1@news-01.bur.connect.com.au...
>
> "nappy" <gospam@yourself.com> wrote in message
> news:6zEOf.27169$_S7.17794@newssvr14.news.prodigy.com...
>> If you are using the FX2 you can use their driver and API and achieve
>> higher data rates than 2MB.
>>
>> What exactly are you trying to do?
>>
>>
>> "Arthur Richards" <fake@address.com.au> wrote in message
>> news:dudisu$cq0$1@news-01.bur.connect.com.au...
>>> We want to use a Cypress FX2 to send 2 MBytes/sec data to a PC via usb.
>>> In order to avoid writing a PC driver I'm considering using HID
>>> interrupt transfers. Latency should be better than 100ms say.
>>>
>>> Can anyone see any problems with this?
>>>
>>> Thanks,
>>> Arthur Richards
>>>
>>
>>
> Thanks for the reply
>
> The data will be streamed continuously from an X-ray line scan array. I
> was considering HID to avoid the cost of the Jungo WinDriver - the
> evaluation copy expires after 30 days I think. This is a low volume
> application and the development cost is significant.
>
> What is the Cypress driver you referred to? Will it do isochronous
> transfers?
Arthur.. I jsut completed a few projects using the FX2 and the CYUSB driver
they supply for free. They have an API (cyapi) which makes it relatively
easy to do Interrupt, bulk and iso transfers. There is information about it
on their website. You can also get a neat littel development board from
bitwise systems to get started right away. It has all of the pins on the FX2
broken out to connectors.
>
> Arthur
>
Reply by Arthur Richards●March 5, 20062006-03-05
"nappy" <gospam@yourself.com> wrote in message
news:6zEOf.27169$_S7.17794@newssvr14.news.prodigy.com...
> If you are using the FX2 you can use their driver and API and achieve
> higher data rates than 2MB.
>
> What exactly are you trying to do?
>
>
> "Arthur Richards" <fake@address.com.au> wrote in message
> news:dudisu$cq0$1@news-01.bur.connect.com.au...
>> We want to use a Cypress FX2 to send 2 MBytes/sec data to a PC via usb.
>> In order to avoid writing a PC driver I'm considering using HID interrupt
>> transfers. Latency should be better than 100ms say.
>>
>> Can anyone see any problems with this?
>>
>> Thanks,
>> Arthur Richards
>>
>
>
Thanks for the reply
The data will be streamed continuously from an X-ray line scan array. I was
considering HID to avoid the cost of the Jungo WinDriver - the evaluation
copy expires after 30 days I think. This is a low volume application and the
development cost is significant.
What is the Cypress driver you referred to? Will it do isochronous
transfers?
Arthur
Reply by nappy●March 5, 20062006-03-05
If you are using the FX2 you can use their driver and API and achieve higher
data rates than 2MB.
What exactly are you trying to do?
"Arthur Richards" <fake@address.com.au> wrote in message
news:dudisu$cq0$1@news-01.bur.connect.com.au...
> We want to use a Cypress FX2 to send 2 MBytes/sec data to a PC via usb. In
> order to avoid writing a PC driver I'm considering using HID interrupt
> transfers. Latency should be better than 100ms say.
>
> Can anyone see any problems with this?
>
> Thanks,
> Arthur Richards
>
Reply by Stef Mientki●March 5, 20062006-03-05
Arthur Richards wrote:
> We want to use a Cypress FX2 to send 2 MBytes/sec data to a PC via usb. In
> order to avoid writing a PC driver I'm considering using HID interrupt
> transfers. Latency should be better than 100ms say.
>
> Can anyone see any problems with this?
I'm not an expert,
but what I remember, HID can never transport 2 MB/s !
Stef
>
> Thanks,
> Arthur Richards
>
>
Reply by Arthur Richards●March 4, 20062006-03-04
We want to use a Cypress FX2 to send 2 MBytes/sec data to a PC via usb. In
order to avoid writing a PC driver I'm considering using HID interrupt
transfers. Latency should be better than 100ms say.
Can anyone see any problems with this?
Thanks,
Arthur Richards