Adding USB thumb-drive support to existing product

You don't strictly need host, you can use OTG... Look at the Freescale Flexis parts, specifically the ColdFire-based ones because they include OTG. It's easy to get started with them because they ship an eval module which consists of the bare CPU mounted on a tiny PCB with

100 mil headers. The eval board is the DEMOJM board. Although not explicitly documented, this board can also be used to program your own boards in-circuit (all you need to do is solder on a 3x2 100mil header).

The s/w stack (at least for your purposes) is free, provided by CMX, source is included, development is with regular C in CodeWarrior.

Thanks Lewin, I'll have a look. Guess I should read up on OTG as well...

I have several spare DEMOJM boards and you are welcome to one if you want it. It comes with 8-bit and 32-bit target boards; I want the 8- bit board, but you're welcome to the 32-bit board and the base, which is everything you need to experiment with the CMX stack. The 8-bit board won't do OTG anyway. A size-limited version of CW is included.

That's incredibly kind of you, Thanks ! Let me do a bit more research prior I take you up on your offer. I'll contact you offline...

Again, Thanks !!!

Luminary Micro has a nice dev board that interfaces with a USB thumb-drive using a USB OTG port. They have a nice dev board with free tools, libraries etc. to help one get started. Only FAT12 and FAT16 are supported due to licensing issues with Microsoft on FAT32.

Regards Anton Erasmus

That's ok - I was at a Freescale seminar where they were giveaways. After the show I asked for more of the 8-bit target boards to build my own circuits, and they said "just take a few more entire kits, we don't have loose target boards". So I did :)

I just got done interfacing a GHIelectronics uALFAT to a dsPIC to be abl to bootload from a USB key. Not too bad (other than writing the part t digest the HEX file and write to flash). It is probably going to be a additional $12 when all said and done in quantity for the project since yo have to purchase the uALFAT and a Maxim part as well. MUCH faster tha writing my own stack, or even using the Microchip one.

uALFAT looks good, but price on their web site is considerably higher than $12 ???

FAT32 or bust...

OK - I did a bit more homework. Your comments and thoughts would be appreciated !

FAT16 only supports up to 2GB memory sticks (at least with "standard" cluster and sector sizes). A 4GB memory stick now costs $20. Ergo, customers will buy and plug sticks that require FAT32 into anything we build now and lives on in the market for a few years. As these customers know where I live, I think I need FAT32 support...

So, how to support FAT32 ?

FTDI Vinculum and GHI uALFAT support FAT32. The GHI uALFAT cost looks like its over our BOM target. GHI sells a library USB stack plus FAT32 for $3500.

TheFreescale Flexis part suggested by Lewin (MCF51JM64) is provided with the CMX_lite library, which only supports FAT16. To get FAT32, we'd need to license the complete CMX library for $4600 per product, or do something different.

MicroChip provides a USB-host stack and FAT16 support, but no FAT32. And their hateful new PIC32 web site crashes FireFox (I'll need to try again with IE), though presumably their 16-bitters would be adequate...

Lewin's DOSFS does support FAT32. I had a look and this looks quite nice, though I didn't find the regression tests or see how to run them at first glance. I understand a few minor fixes are pending review and integration; perhaps I could help here with both. Perhaps I should layer Lewin's DOSFS on top of the Flexis or Microchip USB stack.

Your thoughts and komments ? Thanks in advance, Best Regards, Dave

So use the CMX USB stuff and add FAT32 from elsewhere, either mine (yes I'm late with the fixes) or one of about a zillion other open- source options, depending on whether GPL is a problem for you or not.

Vinculum chip would seem the obvious answer. Even with the socket and supporting parts you're well under the $30 target if built in. Even the VDIP1 DIP module would just about be in there.

By the way, it can also be a USB slave, so that may save something elsewhere on the BOM.