RE: CBM900 hard disk timeout

From: Martin Hoffmann-Vetter <>
Date: Sun, 24 Aug 2014 19:27:30 +0200
Message-ID: <008e01cfbfc0$af525bb0$>
Hello Michau,

> Well, I played with the disk, it was an interesting exercise :-) The
> disk appears to be working well:
> * The LED is ON when DRIVE_SELECT_1 signal is asserted (it must stay
> asserted for the rest of the test).
> * The READY and SEEK_COMPLETE signals come active when the drive
> finishes initialization.
> * The TRACK0 signal is active, so you were right: the drive seeks the
> head to track 0 during initialization.
> * The stepper motor moves the head when I pulse the STEP signal. The
> DIRECTION_IN signal must be asserted since the head is at track 0 and
> must move inward.
> * The TRACK0 signal goes to false when the head moves in.
> * The SEEK_COMPLETE goes to false when the head moves, and then
> returns to true.
> All this means to me that the stepper mechanism is working.

Yes you exercise sounds very good. So the hard drive isn't failed!

> The only problem I found is that the drive does not send any pulses to
> the INDEX line. I don't know why it's that, and whether it is enough
> to confuse the controler into shooting timeout errors. The drive
> itself is able to detect index condition, because when there are no
> disk revolutions, it flashes an error code.

This is a good question. It's possible the INDEX line isn't used.

I think the problem must be the readed data. So there are two case, first the disk isn't formatted, or there are problems zu transfer und decode the data from the disk to the memory. Did the c900 read the data via dma?


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Received on 2014-08-24 18:00:41

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