Is hot swapping TrueIDE mode Compact Flash possible?

Question

Hi.I am using an off the shelf PC motherboard with a TrueIDE boot flash.A RAM-resident system loads from the CF card.  From that point on theCF card is not used (no filesystems mounted).Is it electrically ok to swap an idle card?  Will the new cardconfigure itself into TrueIDE mode upon insertion?I haven't mentioned an operating system on purpose.  Host software Ican deal with - it's the CF card itself and its IDE connection that I'mconcerned about.Tips, advice, scary stories appreciated.Regards,Paul.

larwe · Accepted Answer

It is explicitly not supported in the CompactFlash specification. The power supply pins are mechanically sequenced before any control or data lines (look at the connector), therefore the card will not see TrueIDE strapping at powerup.

If you attempt it, you'll find it does work sometimes, particularly if you ram the card in quickly. It's not something you want to design into your user interface, though.

Paul Marciano · Answer

Thanks for that. I'd heard before that it wasn't supported, and so it's not a requirement for the project. However I had read some comments on a Linux board regarding changes to their IDE driver to possibly support it in the future and it started me wondering if it was a software issue or a hardware one.

Thanks again for the quick response.

Regards, Paul.

larwe · Answer

Many devices with a CF slot run in IDE mode have a FET switching thepower rail to the card so that it can be power-sequenced after fullinsertion, precisely so hot-swapping can be supported.

Is hot swapping TrueIDE mode Compact Flash possible?

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