Hi all,
Can anyone help me out with these questions

*Why we need multiple end points other when (1 EP0,1 TxEP and a 1 RX
EP) will do ??
*What 1/2/3 in the UTMI Level1/2/3 specs.It is not mentioned anywhere
in the UTMI spec.
*Any calculation formulas that help determine my fifo sizes.I am
aiming basically at a maximum ISO tranfer case.
*Which UTMI interface do i choose ? (16 bit/8 bit)

Awaiting your answers
Thanks
Rajesh

On Wed, 2004-02-04 at 17:34, i_rajesh1@rediffmail.com wrote:

Good question, I have never liked this either.

Basically what the USB committee has specified are virtual
channels (they call them endpoints, since this is a point
to point connection).

One USB connection is shared between multiple virtual
channels each being able to receive or transmit only
(except the control endpoint - bizarre ;*) Plus there
is one control channel.

Basically this allows in one device for multiple data
streams with out additional logic (well thats of course
a lie as well ;*). A good example is a USB Video Phone:

- one endpoint for video
- one for audio input
- one for audio output
- plus of course the control endpoint which gives you a
GPIO port of up to 1M bits (keypad)

Of course the above could be multiplexed but for some
obscure reason thats how the USB guy did it.

I personally have never used more than one in and one out
endpoint, besides the control endpoint, but had to pay the
price and implement all the overhead ...





Hmm, read latency vs. write speed ?
Think about it ... it's simple ...



Chose a PHY first then the interface. I believe 8 bit
bi-dir is most common ...

rudi ======================================================== ASICS.ws ::: Solutions for your ASIC/FPGA needs ::: ..............::: FPGAs * Full Custom ICs * IP Cores ::: FREE IP Cores -> http://www.asics.ws/