Building your own flash drive

[Mook Johnson]

Where can I find schematics of a USB flash drive. This is the little sticks
with a 8 gig or so of flash in them that operate like a plug in hard drive.

I have a need to build one of these into a board I'm making. I don't want
to reinvent the wheel if there are reference designs out there.

thanks

 

[Joerg]

Where can I find schematics of a USB flash drive. This is the little sticks
with a 8 gig or so of flash in them that operate like a plug in hard drive.

I have a need to build one of these into a board I'm making. I don't want
to reinvent the wheel if there are reference designs out there.

Don't want to burst your bubble here but unless you plan to build
several million systems a year chances are your cost per chip set will
be higher than buying the sticks at a computer discount store. Maybe you
could crack the shell and place it as a little daughterboard.

 

[mpm]

Where can I find schematics of a USB flash drive. This is the little sticks
with a 8 gig or so of flash in them that operate like a plug in hard drive.

I have a need to build one of these into a board I'm making. I don't want
to reinvent the wheel if there are reference designs out there.

thanks

Does it have to be USB?
There are other memory formats out there.

 

[Jim Yanik]

Does it have to be USB?
There are other memory formats out there.

I wonder if one of the photo mass storage modules would work better than
USB flashdrives? Like Compact Flash or SD memory. I suspect that the add-on
reader/writers for these are just simple connections to the USB cable.
Just add a socket on the PCB.I supose you could solder them in,too.

 

[Tim Williams]

The card reader for my camera's flash ROM shows up as a "USB to IDE"
interface.

On modern hardware, this card reader is plug-and-play and works much like a
thumbdrive. Not too shabby.

Tim

 

[Andy]

Where can I find schematics of a USB flash drive. This is the little sticks
with a 8 gig or so of flash in them that operate like a plug in hard drive.

I have a need to build one of these into a board I'm making. I don't want
to reinvent the wheel if there are reference designs out there.

thanks

USB2230
5th Generation Hi-Speed USB Flash Media & IrDA Controller with
Integrated Card Power FETs
<http://www.smsc.com/main/catalog/usb2230.html>

USB Flash Module
<http://www.transcendusa.com/Products/CatList.asp?FldNo=18&LangNo=0&Func1No=1&Func2No=126>

 

[David L. Jones]

Where can I find schematics of a USB flash drive. This is the little sticks
with a 8 gig or so of flash in them that operate like a plug in hard drive.

I have a need to build one of these into a board I'm making. I don't want
to reinvent the wheel if there are reference designs out there.

thanks

Do you actually need the USB interface or are you just after a bunch
of flash memory?
An SD card is an often used option in this case.

Dave.

 

[Joel Koltner]

I wonder if one of the photo mass storage modules would work better than
USB flashdrives?

If you're "rolling your own" interface and code, compact flash looks just like
an IDE hard drive. A USB memory stick, however, only looks like a hard drive
after you get the USB stack and correct protocol all implemented. I.e., much
more software to write.

SD cards are a little weird, AFAIK -- they complete interface at the "wire"
level is not fully available without NDAs and whatnot, although the SD card
readers use an IC that makes the SD card appear, again, as an IDE hard drive

I suspect that the add-on
reader/writers for these are just simple connections to the USB cable.

No, not at all; the interface ICs for SD cards or USB memory sticks are plenty
complex.

There are SD cards
(http://www.sandisk.com/Products/Catalog(1096)-SanDisk_Ultra_II_SD_Plus_Cards.aspx)
and even CompactFlash cards where they've put that "controller" IC into the
memory card into, and thus the SD card can plug directly into a USB port as
well (and the CompactFlash card reader really was little more than "wires"),
but these are very much the exception rather than the norm. (It never really
made sense for CompactFlash cards either, since unlike the SD card shown at
the link above you still need the mechanical adapter... the idea originally
was apparently that, say, 128MB CF card w/internal USB bridge & mechanical
adapter might be, say, $120 whereas a regular 128MB CF card was, say, $100 and
a full-fledged reader was $80.)

Just add a socket on the PCB.I supose you could solder them in,too.

Indeed -- this is a good idea. It's amazing how cheap flash memory is these
days... It was only something like 5 years ago that we were paying something
like $10 a 2MB flash IC, and today you can get something around a gigabyte for
that much in the form of an SD card or USB memory stick.

---Joel

 

[Mook Johnson]

If you're "rolling your own" interface and code, compact flash looks just
like an IDE hard drive. A USB memory stick, however, only looks like a
hard drive after you get the USB stack and correct protocol all
implemented. I.e., much more software to write.

SD cards are a little weird, AFAIK -- they complete interface at the
"wire" level is not fully available without NDAs and whatnot, although the
SD card readers use an IC that makes the SD card appear, again, as an IDE
hard drive on the far side of a USB link. Hence only the guy who made the


No, not at all; the interface ICs for SD cards or USB memory sticks are
plenty complex.

There are SD cards
(http://www.sandisk.com/Products/Catalog(1096)-SanDisk_Ultra_II_SD_Plus_Cards.aspx)
and even CompactFlash cards where they've put that "controller" IC into
the memory card into, and thus the SD card can plug directly into a USB
port as well (and the CompactFlash card reader really was little more than
"wires"), but these are very much the exception rather than the norm. (It
never really made sense for CompactFlash cards either, since unlike the SD
card shown at the link above you still need the mechanical adapter... the
idea originally was apparently that, say, 128MB CF card w/internal USB
bridge & mechanical adapter might be, say, $120 whereas a regular 128MB CF
card was, say, $100 and a full-fledged reader was $80.)


Indeed -- this is a good idea. It's amazing how cheap flash memory is
these days... It was only something like 5 years ago that we were paying
something like $10 a 2MB flash IC, and today you can get something around
a gigabyte for that much in the form of an SD card or USB memory stick.

---Joel

Those are some good thoughts. I need to store a lot of data on a flash disk
(of
any type) that can be read either by a USB 2.0 link or a wireless USB link.
The desire is to have the embedded system write files to the NTFS file
system and have a windows notebook just plugin and read the files off at
high
speed when the job is done. We're talking a full 2 - 8 GB of data so the
high speed is
needed. The box won't be opened to read the data so just removing
the chips isn't an option unfortunately. Also I'd like to solder the chips
in so the connector doesn't give problems with age moisture and
vibration.

the SD cards look like an interesting option. I was thinking that there
were some reference designs by the IC manufacturers that made their USB chip
with a
flash port on it look like a USB drive. No firmware needed just glue on the
chips and away you go. Nothing like this available?

 

[Nicholas Sherlock]

Where can I find schematics of a USB flash drive. This is the little sticks
with a 8 gig or so of flash in them that operate like a plug in hard drive.

I have a need to build one of these into a board I'm making. I don't want
to reinvent the wheel if there are reference designs out there.

The AT90USBKEY Atmel demonstration board is a USB flash drive out of the
box, source included. It has 16MB of flash on-board for demonstration
purposes. Building a USB drive into your product with the chip that's on
this board would probably be a cinch!

Cheers,
Nicholas Sherlock