RE: 8088 and 610 saga continues...

From: Hoffmann-Vetter, Martin <>
Date: Tue, 25 Jan 2011 23:11:13 +0100
Message-ID: <000d01cbbcdc$c89a1800$1b09a8c0@mhvnb10>

> EVERY byte with address xx21 and xxA1 gets corrupted with random
> values.

So it's the address

> xxxx xxxx x010 0001

Is this only in bank 1? Or the other banks also corrupted? Same addresses?

> It seems likely to me that something is playing very rudely with
> DRAM control lines and overwriting a location in all memory columns at
> once.

The circuit for the signals /busy1 und /busy2 controls who access the dram. Is here an error? When the access is switch via the /busy1 and /busy2 signals at a time with access to the dram, this must corrupt the memory.

> Or maybe it is a different problem. Maybe these locations are not
> overwritten by anything, but they are not refreshed? Something causes
> these two rows to not be refreshed? Does it make any sense?

I don't think so. The refresh makes the 8088 board when the 8088 is running. There is a refresh request signal and the board answer with an refresh grant. The refresh addresses are generated at the CBM-II board.



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Received on 2011-01-25 23:00:09

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