Using D Flip-flops to create a certain sequence pattern

Comments

• Phil Pilgrim (PhiPi) Posts: 23,514

  2020-04-03 00:58 edited 2020-04-03 01:03

  Do your D flip-flops have /preset and /clear inputs (e.g. like 74HC74)? If so, it can be done with three D f/fs.
  
  -Phil
• william chan Posts: 1,326

  2020-04-03 01:48

  Yes, my D Flip Flops have preset and clear inputs.
  How to do it with three flip flops?
• Phil Pilgrim (PhiPi) Posts: 23,514

  2020-04-03 02:37

  This should do the trick (no presets or clears needed, it turns out):
  
  
  
  -Phil

  

  

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• william chan Posts: 1,326

  2020-04-03 03:08

  You are a genius !
  Thanks a million.
• yeti Posts: 818

  2020-04-03 05:58

  A 2 bit shift register and a 2 bit clock divider sharing one DFF, very nice!
  
• macrobeak Posts: 354

  2020-04-03 11:08

  OK Phil, so how did you solve that so quickly?
  I was going to refer William to online simulators but you smashed it first!
• Phil Pilgrim (PhiPi) Posts: 23,514

  2020-04-03 19:26

  macrobeak wrote:

  OK Phil, so how did you solve that so quickly?

  By arranging the desired outputs in a column and recognizing familiar patterns.
  
  -Phil
• yeti Posts: 818

  2020-04-04 01:57 edited 2020-04-04 01:57

  I saw the the pattern after doubling the table to see 2 periods.
  
• Mickster Posts: 2,611

  2020-04-04 11:46

  william chan wrote: »

  You are a genius !

  
  Ya got that right....examples like this make me feel like an intruder in an exclusive club.
  
  
• Beau Schwabe Posts: 6,547

  2020-04-04 16:33 edited 2020-04-05 18:47

  Phil,
  
  Of course this does not go without a "Golf Challenge"
  
  Note: A and C should be swapped in the attached diagram

  

  

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• Phil Pilgrim (PhiPi) Posts: 23,514

  2020-04-04 19:20

  Ha! Clever!
  
  -Phil
• yeti Posts: 818

  2020-04-05 03:26

  Using an XOR when the question was to use DFFs only?
  Golfing the POTUS way?
  Missing the hole and/or bending the rules?
  
  But a nice solution for a related modified question.
  ;-)
• Beau Schwabe Posts: 6,547

  2020-04-05 18:42 edited 2020-04-05 18:45

  Since when have you known me to play by the rules? - lol
  
  Besides technically, the OP stated four DFF, and Phils solution used three. I didn't sense that we were limited to only DFF's.
  
  Attached is another solution using one DFF and some discrete components that form an RTL XOR gate
  
  

  

  

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