I'm attempting to modernize a datalogger by upgrading it from a 2.5 inch
IDE hard drive to two compact flash cards in a 2.5 inch IDE adapter.  My
application is actually almost identical to the one found in this thread:

http://www.embeddedrelated.com/usenet/embedded/show/97443-1.php

I have a 2.5 inch IDE to Compact Flash adapter from Addonics that has both
a master and slave CF slot.  When I populate both slots and plug it into an
external drive enclosure, my XP PC detects and can interact with both
cards.  I believe the adapter works in a Cable Select mode, because the
master's pin 28 is grounded and the slave's pin 28 is not connected to
anything.

When I plug the populated adapter into my datalogger, I can only interact
with the card in the master/Device 0 slot.  When I try to read the slave
card's status register I never get a DRDY (device ready) bit set.  

My level of interaction is with the actual device registers, i.e. setting
the number of sectors to write, giving an address to the
sector/cylinder/head registers and then issuing a Write Sector command.
The language I'm using is C, if it matters.

I've been using the ATA-ATAPI-5 specification to try to learn how to deal
with two devices on the same IDE port, but it seems to imply that switching
devices with the DEV bit in the device/head register should just work.

Is there anything special I need to do, perhaps at startup, to get the two
cards to configure themselves properly?

Thanks much!

---------------------------------------        
This message was sent using the comp.arch.embedded web interface on
http://www.EmbeddedRelated.com