>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

This sounds like it really needs a PIC32 with USB-to-Go, but maybe you could 
do an interface like someone did with an AVR (IIRC) to do USB interface like 
a 4550. Whether one would have enough code space to do the equivalent in the 
reverse direction is another matter.

But if they are already using a 4550 why not have it save the data 
internally and then download from that ??? If it is remote from where the PC 
is then I guess the other solution is to use an SD card in SPI mode, and use 
a USB reader to read that.

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