problem using CompactFlash Card in True IDE mode

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originally posted by bonehead@Oct 21 2005, 03:49 AM

i just want to add a cf card to my system based on nios3.0 and i hope it works in true ide mode.

but when i refere to the "compactflash specification revision 3.0", it says that the true ide pio mode has 7 modes(mode0~mode6),and it has different read/write times from each other. i am confused now. are these modes decided by the cf card itself or we can configure it to work at some mode ?if it is configurable ,how to ?

thanks for your reading and regret for my poor english.

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Bonehead:

I have been working with the CF components over the last few days. The Identify Device Information block, offset 163, contains the maximum mode supported by the drive. In my case using the SanDisk 32meg card suppied with Cyclone II Dev Kit supports upto and including mode 4. All I had to do was modify the timing as follows:

Given Mode 4 Timings:

T0(Cycle Time) = 120ns

T1(Setup Time) = 25ns

T9(Addr Hold) = 10ns

Setup = T0 = 25ns

ReadWait = T0 - T1 = 95ns

WriteWait = T0 - T1 - T9 = 85ns

Hold = T9 = 10ns

These values are working in my system and all of the tests in the software provided are passing. I hope this helps.

Best of luck,

Graham....