>Hi All,
>
>Thinking of emperimenting with USB, and would like to stick with a
>flash chip, but I've noticed that Microchip on has USB in the 'C'
>chips.
>
>Anyone done any simple USB w/o a USB-supported chip (like any of the
>F84, F628, F87x, etc)?  I'd really appreciate some sample code or
>starting info on how to do this.
>
>Thanks, -Neil.
>
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>
>

> (all in the FTDI chip) or PC end (FTDI supplies them!)
>
> FTDI sells the chips in small quantities from their web site for a
> reasonable price too.
>
> http://www.ftdichip.com/FTProduct.htm
>
> Matt Pobursky
> Maximum Performance Systems
>
> On Sat, 28 Sep 2002 13:45:26 -0400, Pic Dude wrote:
>> Hi All,
>>
>> Thinking of emperimenting with USB, and would like to stick with a
>> flash chip, but I've noticed that Microchip on has USB in the 'C'
>> chips.
>>
>> Anyone done any simple USB w/o a USB-supported chip (like any of

> Matt Pobursky wrote:
>> Any PIC + FTDI chip (parallel for speed, serial for low pin count)
> is
>> about the easiest way to go. You can be up in about 5 minutes once
> you
>> have the circuit connected, no drivers to write on either the PIC
> side
>> (all in the FTDI chip) or PC end (FTDI supplies them!)
>>
>> FTDI sells the chips in small quantities from their web site for a
>> reasonable price too.
>>
>> http://www.ftdichip.com/FTProduct.htm
>>
>> Matt Pobursky
>> Maximum Performance Systems
>>
>> On Sat, 28 Sep 2002 13:45:26 -0400, Pic Dude wrote:
>>> Hi All,
>>>
>>> Thinking of emperimenting with USB, and would like to stick with a
>>> flash chip, but I've noticed that Microchip on has USB in the 'C'
>>> chips.
>>>
>>> Anyone done any simple USB w/o a USB-supported chip (like any of
> the
>>> F84, F628, F87x, etc)? I'd really appreciate some sample code or
>>> starting info on how to do this.
>>>
>>> Thanks, -Neil.
>
>
> The FT8U245AM is really amazing @ $5.75 for single quantity.
>
>
> /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
> Wagner Lipnharski - UST Research Inc
> Orlando FLorida - USA - http://www.ustr.net
> /_/_/_/ Atmel AVR Consultant /_/_/_/
>
> --
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> RemoveMEpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu
>
>

> To expand on what Alan said with an example, the quickest path to get
> up and running with the FTDI chip is this.  Take a working design
> that current uses a serial port.  Add a FTDI serial chip to the
> board.  The existing design's serial interface just connects to the
> FTDI chip.  Don't modify the firmware at all.  When you plug it into
> a PC, install the default drivers that FTDI distributes.  They will
> just add a serial port to the PC - say COM4.  Now take the existing
> software for the old design and configure it to use COM4. The old
> firmware and PC software both still work without modification.  They
> think they are still using a serial port.
>
> FTDI makes an evaluation cable that you can just plug into your serial
> product.  It gives you the same user experience.  If you like it, put
> the chip on the board.
>
> The Rabbit dev environment uses a serial connection to their core
> modules. They sell the FTDI eval cable as an option.  When using it,
> you can get 240 baud (or something like that), so it does go a little
> faster than a standard serial cable - probably because the single
> ended serial singles are so short.

>
> If you take a little dev time, you can change your design and
> firmware to use the parallel interface FTDI chip instead of RS232
> serial.  I would think that the clocked parallel interface would not
> limit the through much - if at all. (don't really know, though)
>
> So Neil, I would say that if your purpose is to learn about USB, do
> not use the FDTI chip.  It hides all the details of USB from you
> which is good for updating an existing product quickly, but not for
> learning.  With a normal USB stack, you will determine how your
> device is identified on the bus, what services/interfaces it
> supports, and be able to choose how to send data - streaming or
> asynchronously (I can't remember the real terms for these two right
> now).  That's what USB is all about.
>
> As far as the PC software goes, you have a choice of having your
> device support one of the built-in interfaces or writing your own
> driver.  One of the built-in interfaces is the storage interface.
> That is why you can plug a USB memory/hard disc into a WinXP computer
> for the first time and it will work without installing any drivers.
> I don't know if there are any other common interfaces included in
> WinXP or other OS.
>
> --BobG
>

> The limitation is the single ended serial connection between the FTDI
> chip and your hardware.  Since the FTDI chip is physically close to
> your device, you can get away with higher rates than in the general
> case where a cable might be 10's or 100' of feet long.  Of course, as
> you pointed out the firmware needs to be able to select a higher rate.
>
> The Rabbit dev kit I have (RS232 serial peripheral --> FDTI eval
> cable --> FDTI virtual serial port driver) runs at something like 240
> baud.  If you succeed in convincing me that it can't be done, I will
> stop using it as I would not want to violate any laws of physics:)