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Re: Can anyone see a way to improve this ?

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On Tuesday, 28 October 2014 04:21:56 UTC+10, mjm...@aol.com  wrote:

> I think I'd test two patterns, $55 and $AA, and only look for which bit
> fails if any of them do. 

Yeah - I've already implemented this one as a faster "QC Passed" test. The 'walking ones' style test above (with the redundant Y-register use and one level of unroll) takes approximately 1 hour to test 16MB of RAM. Unfortunately all extant accelerators violate the spirit of the test :-)

> Single bit errors in RAMs tend not to be crosstalk errors, where all other
> bits can cause the bad one to flip--in other words, the bits can be
> considered independent. 

These particular chips are 0.5mm pin-pitch TSOP packages, so I was more concerned about crosstalk due to a poor solder joint making an air-gap capacitor between two adjacent address/data pins.

Matt

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Can anyone see a way to improve this ? mdj <mdj.mdj@gmail.com> - 2014-10-27 05:04 -0700
  Re: Can anyone see a way to improve this ? "Anton Treuenfels" <teamtempest@yahoo.com> - 2014-10-27 08:38 -0500
  Re: Can anyone see a way to improve this ? Vladimir Ivanov <none@none.tld> - 2014-10-27 15:56 +0200
    Re: Can anyone see a way to improve this ? Michael J. Mahon <mjmahon@aol.com> - 2014-10-27 13:21 -0500
      Re: Can anyone see a way to improve this ? mdj <mdj.mdj@gmail.com> - 2014-10-27 17:48 -0700
        Re: Can anyone see a way to improve this ? Snertking <SNERTKING@GMAIL.COM> - 2014-10-27 21:28 -0400
          Re: Can anyone see a way to improve this ? mdj <mdj.mdj@gmail.com> - 2014-10-27 22:45 -0700
            Re: Can anyone see a way to improve this ? Michael J. Mahon <mjmahon@aol.com> - 2014-10-29 10:33 -0500
              Re: Can anyone see a way to improve this ? mdj <mdj.mdj@gmail.com> - 2014-10-29 22:54 -0700
                Re: Can anyone see a way to improve this ? qkumba <peter.ferrie@gmail.com> - 2014-10-31 14:46 -0700
      Re: Can anyone see a way to improve this ? Snertking <SNERTKING@GMAIL.COM> - 2014-10-27 21:25 -0400
      Re: Can anyone see a way to improve this ? michael.pohoreski@gmail.com - 2014-12-30 10:12 -0800
  Re: Can anyone see a way to improve this ? awanderin <awanderin@gmail.com> - 2014-10-27 21:35 -0600

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