Re: 6702 chip

From: William Levak <wlevak_at_SDF.ORG>
Date: Thu, 17 May 2012 04:45:36 +0000 (UTC)
Message-ID: <Pine.NEB.4.64.1205170428430.754@sdf.lonestar.org>
On Mon, 14 May 2012, William Levak wrote:

> On Sat, 12 May 2012, William Levak wrote:
>
> I wrote a basic routine to calculate the expexted numbers and compare them to 
> the ones actually produced by the 6702.  I ran this for several thousand 
> write and read cycles.  They matched.  Then I modified the routine to write 
> every even number for each 420 number cycle, 53760 cycles.  They all matched.
>
> The value of the even number doesn't appear to matter, at least when the odd 
> number is one.

I tried several variations of the above routine.

      1) I put an extra even number write before the even odd pair.
      2) I put an extra odd number write after the even odd pair.
      3) I put in extra reads after the even odd pair.

None of these thing affected the output.  It seems clear that only an even 
odd pair of writes affects the 6702. Everything else is ignored.

For this reason I concluded it is not necessary to test every possible 
even number for the entire non-repeating sequence.  I have therefore 
changed the routine to use random even numbers. I run the routine for at 
least a thousand numbers to be sure I get a good even number sample, or as 
long as necessary to go through the non-repeating sequence.  Some of the 
sequences are 1680 numbers long.

I am up to 19 testing the odd numbers.  I should be able to go through all 
128 in several days.


wlevak@sdf.lonestar.org
SDF Public Access UNIX System - http://sdf.lonestar.org

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