Re: Building your own flash drive
- From: "Mook Johnson" <mook@xxxxxxxx>
- Date: Fri, 9 Nov 2007 19:22:29 -0600
"Joel Koltner" <JKolstad71HatesSpam@xxxxxxxxx> wrote in message
news:13j9438atpb2gcc@xxxxxxxxxxxxxxxxxxxxx
"Jim Yanik" <jyanik@xxxxxxxxx> wrote in messageThose are some good thoughts. I need to store a lot of data on a flash disk
news:Xns99E2EEBA93507jyanikkuanet@xxxxxxxxxxxxxx
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 on the far side of a USB link. Hence only the guy who made the
USB<-->SD interface IC needed to sign all those NDAs...
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
(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?
.
- References:
- Building your own flash drive
- From: Mook Johnson
- Re: Building your own flash drive
- From: mpm
- Re: Building your own flash drive
- From: Jim Yanik
- Re: Building your own flash drive
- From: Joel Koltner
- Building your own flash drive
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