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NES Controller 4021 Shift Register Parallel In Serial Out

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    NES Controller 4021 Shift Register Parallel In Serial Out

    So this chip on my NES controller has gone bad HD14021BP (datasheet http://pdf1.alldatasheet.com/datashe.../HD14021B.html)

    Now I can get the same exact one from aliexpress but it'll take weeks and there a few £.

    Found this 4021 on cpc for 40p, my only concern is the frequency http://cpc.farnell.com/nxp/hef4021bp...15v/dp/SC08655

    Anyone able to provide any info on whether the frequencies need to directly match?

    #2
    Re: NES Controller 4021 Shift Register Parallel In Serial Out

    any 4021 will do, it's only running at 5v and clocking slowly.
    the cpu only runs at about 2mhz!

    more:
    http://uk.farnell.com/nxp/hef4021bp/...-15v/dp/384800
    http://uk.farnell.com/texas-instrume...18v/dp/2256617

    btw, the frequency is the maximum, it can run at any speed you want upto that rating.
    Last edited by stj; 08-14-2015, 11:43 AM.

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      #3
      Re: NES Controller 4021 Shift Register Parallel In Serial Out

      What I find interesting on your data sheet is that the Maximum clock frequency is less then the typical clock frequency. That is puzzling?

      Comment


        #4
        Re: NES Controller 4021 Shift Register Parallel In Serial Out

        Originally posted by keeney123 View Post
        What I find interesting on your data sheet is that the Maximum clock frequency is less then the typical clock frequency. That is puzzling?
        just an error in the datasheet, they got the columns the wrong way around.

        Comment


          #5
          Re: NES Controller 4021 Shift Register Parallel In Serial Out

          Originally posted by stj View Post
          any 4021 will do, it's only running at 5v and clocking slowly.
          the cpu only runs at about 2mhz!

          more:
          http://uk.farnell.com/nxp/hef4021bp/...-15v/dp/384800
          http://uk.farnell.com/texas-instrume...18v/dp/2256617

          btw, the frequency is the maximum, it can run at any speed you want upto that rating.
          Thanks, so that one from CPC will do fine?

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            #6
            Re: NES Controller 4021 Shift Register Parallel In Serial Out

            yes

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              #7
              Re: NES Controller 4021 Shift Register Parallel In Serial Out

              Originally posted by stj View Post
              yes
              thanks for your help

              Comment


                #8
                Re: NES Controller 4021 Shift Register Parallel In Serial Out

                Just a follow up, replaced with the part I linked to from CPC, controller now works fine

                Thanks for your help again

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