Groups > sci.electronics.design > #458415

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	2017-05-02 11:30 -0400
Organization	A noiseless patient Spider
Message-ID	<oea8ft$vu8$2@dont-email.me> (permalink)
References	(11 earlier) <2644fbfb-1118-4e21-b652-fb607f27313a@googlegroups.com> <oe5u7j$tqu$1@dont-email.me> <66cd68dd-8700-4835-b226-e2d7a1c5e5f4@googlegroups.com> <oe7abv$48d$1@dont-email.me> <a7fdd9b5-a64a-46b8-b37a-a885424cd56f@googlegroups.com>

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On 5/2/2017 2:02 AM, bill.sloman@ieee.org wrote:
> On Monday, May 1, 2017 at 10:43:48 PM UTC+10, rickman wrote:
>> 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.
>
> Johnson/ring counters don't need decoders because the counter has as many bistables as it has states. Only one bistable is set in any one state.
>
> The output isn't a Gray code - two outputs change state at once.

I think you need to go back to google and check on that.  You are 
confusing a Johnson ring counter with a one-hot or Overbeck ring counter.

https://en.wikipedia.org/wiki/Ring_counter

-- 

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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