Compact Flash busy bit constantly set

This is a repost of the above message with more explicit formatting.

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I have a Compact Flash card that was used in a custom long-term datalogger that ran to battery depletion. After recovery, the card is not recognized by the disk management tools in Windows XP, Mac OSX or Ubuntu Linux. It should have data on it, and I would like to recover that data if possible.

It is certain that the logger went through a marginal power state as the batteries failed, and may have browned out in the middle of a write.

I've played with the card in a test environment, and am able to read and write at least the HEAD, SECTOR_NUMBER and CYLINDER_LOW registers. I can also read the STATUS Register. The STATUS Register read always returns

operations.

Is there any way I can reset the card without destroying the data, access the data with a different protocol, or otherwise save the CF card?

Thanks!

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It is not possible to do any operation while the card is in BUSY state. Try forcing the hardware reset, and then doing all operations in the slowest PIO mode (PIO-0). If the card doesn't come up into READY state after few hundred milliseconds after reset, then the card is broken.

If your data is really worth it, you can unassemble the broken card and read raw information directly from NAND chips.

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

Thank you for the suggestions! I will see what I can do.

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