I wrote to Pascal Dornier (pdornier@pcengines.com) which makes CF IDE adapters (unfortunately going the wrong way for our purposes). He wrote the following back... perhaps it'll be helpful... here is his reply regarding a CF to IDE adapter (to permit an IDE disk to run off the CF adapter, note he didn't understand in this reply the specific application device we are targeting thus his reply is a bit generic)...
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It is basically possible, but I don't see enough demand to make this a worthwile product for me.
Some pitfalls:
- CF card can run in ATA or in PC card mode. PC card mode is more complicated, and would require some glue logic.
- 2.5" drives run on 5V, most PDA's will probably use 3.3V supply for the CompactFlash card. Signaling levels need to be translated.
I think you would be better off using something like the IBM Microdrive.
Pascal
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He can be reached via the above email his site is at http://www.pcengines.com