27 Feb
2014
27 Feb
'14
6:29 p.m.
On Tue, Feb 25, 2014 at 05:02:14PM -0800, Rick Bensene wrote:
Using FUTIL, I can read in a block, change any but the first word in the
block, and write it out, then read it back, and it's fine. I can do
this with words 1 through 255 of any of the blocks on the disk.
However, if I read in a block, change the first word (word 0) of the
block, and write it out, then read it back, the first word is as I set
it to be -- but, if I read any other block, the first word is always the
same as what I wrote out.
Is this likely because the write and read buffer is the same memory and
when you do a read the first word is not being modified so is the last
written word? If you know where the buffer is change the first word before
the read and see if it gets modified.
Does anyone out there have any ideas what I could do
to track this down
further? The RK8E is the only data break device I have in the system,
everything else uses programmed data transfers, so I can't try with
another data break device and see if the behavior is consistent.
What test equipment do you have? Since you said one word transfers didn't
work that may be easiest to start with. Looking at the control signals you
should be able to tell if the dma write doesn't happen or what goes wrong.