File System for "disk-on-key" device

Jan 26, 2005 3 Replies

Hello, everyone ! It's my first time here. Really great resource. I have one tiny question. I will really appriciate if anyone can help me out with it.



We are developing a "camera on a stick". It is actually a CMOS sensor camera with a very simple Micro controller which supports the USB 2.0 protocol and MPEG2 encoder chip. The idea is that the camera will compress rather small video clips in MPEG2 format to the external "disk-on-key" (for example of M-Systems) connected to the camera all the time during video capturing. When the disk-on-key is inserted to a computer USB it should be automatically accessable by Windows Explorer without installation of any driver software.



The problem we face is how to support the Windows File system without using high-end controllers (ARM for example) with an operating system running on it. We are really interested in keeping the price of the device as low as possible.



As far as I understand today every digital camera, every Voice recorder, MP3 player with USB support faced the same problem. Thank you very much.



Alex Zaretsky.


Supporting FAT is not a big task and can easily be done in an 8-bit microcontroller. The hard part is the USB stack. Better to pick a USB host chip that has existing IP (maybe built-in). Look at Atmel's parts for example, which are designed to solve this problem for you.

Hi Alex. I don't know if this will help you but here's another idea. If you could record the data to a compact-flash memory card, they have a nearly identical pinout and functionality to an IDE hard disk. Then you only need an USB --> IDE interface, which have become so popular.

Cypress seems to make some nice USB micro hubs, one of these might be worth checking out. See:

formatting link

-- "The knowledge is worth 10x more than the solution." MCJ 200401

Yes, then it is time to consider a USB host adapter chip. It acts like a PC and aceesed the Flash sticks. There is Cypress and the Atmel USB380 plus more. the newsgroup comp.arch.embedded might also be more appropriate. Look out for "USB host" there.

Rene

Ing.Buero R.Tschaggelar - http://www.ibrtses.com & commercial newsgroups - http://www.talkto.net

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