I think you need a USB-On-The-Go to be able to do that. As far as I concern
the SIE in PIC is not allow you this, but there are some  devices that may
can do the trick.

http://en.wikipedia.org/wiki/USB_On-The-Go
http://www.maxim-ic.com/appnotes.cfm/appnote_number/1822/

Hope it helps
Tamas


On Wed, Jun 11, 2008 at 11:55 AM, Jinx <joecolquitt@clear.net.nz> wrote:

> Xiaofan, a client has asked if a USB memory stick (which I think
> is what you're calling a thumb drive) can be added to a 4550 to
> log analogue readings and general data
>
> I've had a look through some of the links you provided, especially
> those that mentioned mass storage. I'm aware that the 4550 is not
> a host, as you point out in the quote below. Do you know if anyone
> has a work-around ? Perhaps a peripheral adapter ? A thumb drive
> would be most convenient for end users (write with PIC, read with
> PC) so I'll pretty much do what it takes if it's possible
>
> =================
>
> http://forum.microchip.com/tm.aspx?m=304436
>
> Description:
> Will the full speed usb PIC18Fxx5x device, talk to a usb thumb-drive?
>
> Resolution:
> The PIC18Fxx5x (such as the PIC18F4550) cannot be a usb host
>
> This means that you can build any device that is a slave device.  This
> basically means that you can connect the PIC18F4550 to a PC, and
> program it to be a lave.  However you can not connect a device to
> the PIC18F4550 that would need to connect to a PC. This means
> you could put code on the '4550 to read a memory card and provide
> the data to a PC, but you could not program the '4550 to read a
> thumb drive, as the thumb drive needs a host, such as a PC
>
> The reason the thumb drive doesn't work is that the typical usb
> thumb drive is a 'slave only' device just like the PIC18F4550. Thus
> the PIC18F4550 cannot talk directly to a thumb drive is a slave
> device can not talk to a slave device
>
> --
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-- 
Rudonix DoubleSaver
http://www.rudonix.com
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