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CF cards and changing PIO modes (to enable IORDY)

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TomS_:
Hi all.

Im trying to enable the IORDY signal on a CF card. The capabilities word obtained from an "identify" command states that it is supported (along with PIO modes 3 and 4 where this signal is mandatory).

It seems I should only need to use the "set features" command with feature 3 and supply the appropriate value, in this case 0xB (1011) to enable PIO mode 3 and IORDY.

I do this, and the drive does not report any errors in either the status or error registers suggesting that it accepted the command, but I never see the IORDY signal toggling when reading/writing after that.

Has anyone ever done anything like this before and knows the process? Ive been googling for hours looking at any and all documents about IDE, ATA, PIO, etc that I can find and they all seem to suggest about the same thing so Im not sure what Im doing wrong.

Thanks!

Postal2:
As far I remember, IORDY reports about interface, not media. Will be set shortly when too big data sending. Small chunks will not affect him. When IORDY is active - computer is fully stopped (true for BIOS routines).

TomS_:
Yes that is correct, and I want to use it on the interface side of things to time bus cycles according to the CF cards ability to complete them.

The specific use case is to tie IORDY into the generation of the DTACK signal in a Motorola 68000 system.

Postal2:
IORDY as I know is fatal error indicator, it is not an irq request. It is signal of interface only, not bounded to busy of media. Of course, you can use it with your own low-level non-standard routines. To activate this signal you must overload data path (send too much data).

TomS_:
I know its not an IRQ. But the datasheets do not mention anything about it being an error signal as such.

Do you mean to say that the IORDY signal might only be activated sometimes, if the CF card is too busy?

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