CF HOT SWAP

  • Thread starter Thread starter tgomez
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tgomez

Hi ALL,

I am currently working on a system that is supposed to have "hot
swap" capability for a CF card. I was thinking about interfacing this
directly to IDE but started to read a bit about how you need to have a
"cardbus controller" so that it will control the spontaneous device
eject.

Is there a way to have the CF card interfaced to an IDE channel and
still be "hot swap" enabled.

tks...
Tony
 
Hi Tony,

Look at the thread from few days ago about similar subject.
Anyhow I have been told that this can't be done. I have not used this nor
read the CF specs, but I will think aloud and you consider it by your self.

First there are many people in other NG that tell CF on IDE does not play
nicely with hot-swap.
CF is hot-swappable by default since it work on USB readers so it is not a
problem.
IDE disks are... well it is hard to say since physically it is very
dangerous to play with wide IDE cables it could do some electrical problems
(I'm not interested in software side of problems related to this.)
Since IDE cable goes to CF Reader electronic we don't have problems with
that side since CF reader will "buffer" (hide) IDE side from CF side.

So now there is a question whether CF reader is smart enough to handle
properly CF device connected to it or not?
Other question could be how MS drivers by default will react to media
change.

First part you can solve by trying to find CF adapter that can do "stuff"
required by hot-swap.

Second part you will have to try and see what will happen. If it does not
work by default then you will need custom driver.

Regards,
Slobodan

PS:
Check: http://www.adtron.com/pdf/SDDB-sum053004.pdf
 
Tony,

Nope... (go read some of my comments in the 'Removing CF from IDE Bus'
thread). CF on IDE is by design not hot swapable.
CF in a USB reader is.. it's all in how the CF card wakes up on power up.

Dave
 
Guys, thanks for you input...

The device I am working on will have an internal CF card in *fixed
mode* connected to an IDE channel. This will be OS files and the
application. The external CF - hot swappable etc... was to be as a
remove card storage system. It seems as if maybe we should just use
the USB ports that will be exposed and instead of giving them a CF card
give them a thumb drive. They are inexpensive now-a-days. Sigmatel
seems to make a good flash controller even if we ever wanted to make
our own.

- Again, thanks for valuable information...
tony
 
If you have USB then it will be much easier and better to use it for
physicaly removable devices. (From both hardware and software point of view)

Regards,
Slobodan
 
I'm with Slobodan on this.

USB Thumb drive will be much better from a software point of view. Even
though you *should* do an device eject, the USB drivers seem to be pretty
robust about a 'surprise removal'.

Dave
 
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