Groups > sci.electronics.design > #458221

Re: Binary counter - please check my work

From	rickman <gnuarm@gmail.com>
Newsgroups	sci.electronics.design
Subject	Re: Binary counter - please check my work
Date	2017-05-01 08:43 -0400
Organization	A noiseless patient Spider
Message-ID	<oe7abv$48d$1@dont-email.me> (permalink)
References	(9 earlier) <2210d2d0-3584-46ce-bec3-542d24ee6a83@googlegroups.com> <oe3tah$klv$1@dont-email.me> <2644fbfb-1118-4e21-b652-fb607f27313a@googlegroups.com> <oe5u7j$tqu$1@dont-email.me> <66cd68dd-8700-4835-b226-e2d7a1c5e5f4@googlegroups.com>

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On 4/30/2017 9:52 PM, bill.sloman@ieee.org wrote:
> On Monday, May 1, 2017 at 10:10:33 AM UTC+10, rickman wrote:
>> On 4/30/2017 2:28 AM, bill.sloman@ieee.org wrote:
>>> On Sunday, April 30, 2017 at 3:42:51 PM UTC+10, rickman wrote:
>>>> On 4/30/2017 12:53 AM, bill.sloman@ieee.org wrote:
>>>>> On Sunday, April 30, 2017 at 1:43:55 PM UTC+10, rickman wrote:
>>>>>> On 4/29/2017 11:34 PM, bill.sloman@ieee.org wrote:
>>>>>>> On Sunday, April 30, 2017 at 12:29:55 AM UTC+10, rickman wrote:
>>>>>>>> On 4/29/2017 1:44 AM, Don Y wrote:
>
> <snip>
>
>>>>> Gray code counters don't produce long glitches either, but variation in propagation delays does ensure that transient false states will exist, and can be decoded by a strictly combinational decoder (if it is fast enough).
>>>>
>>>> Nonsense.  Gray code counters are registered like all counters just as
>>>> you said above.  They produce no glitches on the output because only one
>>>> bit changes at a time unlike binary counters where multiple bits change
>>>> at once with unpredictable skew making decoders glitch.
>>>
>>> Oops. I got that wrong. Long time since I looked at Gray codes.
>>>
>>> The decoded output is going to be wrong while the change is propagating through the decoder (which may not be a single stage device, which can be another source of glitches).
>>
>> What decoder?  Again you are making assumptions about some design which
>> may or may not be relevant and so is not a general rule.
>
> If there wasn't some kind of decoder there wouldn't be a problem to have a discussion about. Johnson/ring counters don't need decoders, but that wasn't where the thread started.

Of course Johnson ring counters need decoders.  They are very simple and 
decode without glitching because the counter is a Gray code but decoders 
are still required.  The only FSM that needs no decoder for individual 
states is a one-hot FSM.

-- 

Rick C

Thread

Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-04-28 19:14 -0400
  Re: Binary counter - please check my work Don Y <blockedofcourse@foo.invalid> - 2017-04-28 16:20 -0700
    Re: Binary counter - please check my work rickman <gnuarm@gmail.com> - 2017-04-28 19:31 -0400
    Re: Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-04-28 22:39 -0400
      Re: Binary counter - please check my work Don Y <blockedofcourse@foo.invalid> - 2017-04-28 20:07 -0700
        Re: Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-04-29 00:27 -0400
          Re: Binary counter - please check my work Don Y <blockedofcourse@foo.invalid> - 2017-04-28 22:44 -0700
            Re: Binary counter - please check my work Don Y <blockedofcourse@foo.invalid> - 2017-04-28 22:46 -0700
            Re: Binary counter - please check my work rickman <gnuarm@gmail.com> - 2017-04-29 10:29 -0400
              Re: Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-04-29 11:07 -0400
              Re: Binary counter - please check my work bill.sloman@ieee.org - 2017-04-29 20:34 -0700
                Re: Binary counter - please check my work rickman <gnuarm@gmail.com> - 2017-04-29 23:43 -0400
                Re: Binary counter - please check my work bill.sloman@ieee.org - 2017-04-29 21:53 -0700
                Re: Binary counter - please check my work rickman <gnuarm@gmail.com> - 2017-04-30 01:42 -0400
                Re: Binary counter - please check my work bill.sloman@ieee.org - 2017-04-29 23:28 -0700
                Re: Binary counter - please check my work rickman <gnuarm@gmail.com> - 2017-04-30 20:10 -0400
                Re: Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-04-30 20:26 -0400
                Re: Binary counter - please check my work rickman <gnuarm@gmail.com> - 2017-04-30 21:07 -0400
                Re: Binary counter - please check my work rickman <gnuarm@gmail.com> - 2017-04-30 21:20 -0400
                Re: Binary counter - please check my work bill.sloman@ieee.org - 2017-04-30 18:52 -0700
                Re: Binary counter - please check my work rickman <gnuarm@gmail.com> - 2017-05-01 08:43 -0400
                Re: Binary counter - please check my work krw@notreal.com - 2017-05-01 13:33 -0400
                Re: Binary counter - please check my work bill.sloman@ieee.org - 2017-05-01 23:02 -0700
                Re: Binary counter - please check my work Jasen Betts <jasen@xnet.co.nz> - 2017-05-02 11:42 +0000
                Re: Binary counter - please check my work bill.sloman@ieee.org - 2017-05-02 06:10 -0700
                Re: Binary counter - please check my work upsidedown@downunder.com - 2017-05-03 03:26 +0300
                Re: Binary counter - please check my work pcdhobbs@gmail.com - 2017-05-02 18:41 -0700
                Re: Binary counter - please check my work bill.sloman@ieee.org - 2017-05-02 19:39 -0700
                Re: Binary counter - please check my work rickman <gnuarm@gmail.com> - 2017-05-02 11:30 -0400
          Re: Binary counter - please check my work Jasen Betts <jasen@xnet.co.nz> - 2017-04-29 20:25 +0000
            Re: Binary counter - please check my work rickman <gnuarm@gmail.com> - 2017-04-29 23:15 -0400
              Re: Binary counter - please check my work upsidedown@downunder.com - 2017-05-01 11:12 +0300
        Re: Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-04-29 00:43 -0400
          Re: Binary counter - please check my work Winfield Hill <hill@rowland.harvard.edu> - 2017-04-29 05:31 -0700
            Re: Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-04-29 09:48 -0400
          Re: Binary counter - please check my work Don Y <blockedofcourse@foo.invalid> - 2017-04-29 08:45 -0700
            Re: Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-04-29 12:51 -0400
              Re: Binary counter - please check my work rickman <gnuarm@gmail.com> - 2017-04-29 14:54 -0400
              Re: Binary counter - please check my work Don Y <blockedofcourse@foo.invalid> - 2017-04-29 12:34 -0700
                Re: Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-04-29 15:51 -0400
                Re: Binary counter - please check my work Don Y <blockedofcourse@foo.invalid> - 2017-04-29 21:37 -0700
            Re: Binary counter - please check my work Jasen Betts <jasen@xnet.co.nz> - 2017-04-29 20:49 +0000
              Re: Binary counter - please check my work Don Y <blockedofcourse@foo.invalid> - 2017-04-29 14:08 -0700
              Re: Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-04-29 17:31 -0400
                Re: Binary counter - please check my work Jasen Betts <jasen@xnet.co.nz> - 2017-04-30 00:51 +0000
                Re: Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-04-29 21:42 -0400
          Re: Binary counter - please check my work bloggs.fredbloggs.fred@gmail.com - 2017-04-29 12:17 -0700
            Re: Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-04-29 15:36 -0400
              Re: Binary counter - please check my work bloggs.fredbloggs.fred@gmail.com - 2017-04-30 08:00 -0700
                Re: Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-04-30 11:13 -0400
                Re: Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-04-30 11:24 -0400
                Re: Binary counter - please check my work bloggs.fredbloggs.fred@gmail.com - 2017-04-30 08:30 -0700
                Re: Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-04-30 16:06 -0400
  Re: Binary counter - please check my work Jasen Betts <jasen@xnet.co.nz> - 2017-04-29 00:04 +0000
  Re: Binary counter - please check my work bill.sloman@ieee.org - 2017-04-28 21:14 -0700
  Re: Binary counter - please check my work stratus46 <stratus46@yahoo.com> - 2017-05-01 01:51 -0700
    Re: Binary counter - please check my work stratus46 <stratus46@yahoo.com> - 2017-05-01 01:56 -0700
      Re: Binary counter - please check my work bitrex <bitrex@de.lete.earthlink.net> - 2017-05-01 13:36 -0400

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