Re: adding USB Flash feature to existing product (Vinculum? experience?)



Peter Dickerson wrote:

I'm looking into adding support for USB Flash sticks to a current design, perhaps even for retrofit.

[...]

My first thought was the Vinculum VNC1L to take most of the design work away and because the SPI interface would allow it to bolt on. Has anyone here had experience of this chip that they would be willing to share (good or bad) ?

It works OK, however the transfer rate is only about 300kbytes/sec in the best case.

My second thought was to use a host controller chip on the bus (16-bit SRAM-like) which would would not allow retrofit but would give more flexibility and hopefully be cheaper and faster. The problem is developing the software - the thing is OS-less but knows about file system for SD cards (and SDHC). Anyone have experience of this approach with suggestions for a host controller chip and the difficulty of driving it?
Performance doesn't have to be great. The current SD Card incarnation can do file copy at ~70Kbyte/sec.

We ended up doing the Compact Flash interface. This is much simpler on the hardware and software, and the performance is at the order of tens of megabytes per second.

Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com


.