NES Controller 4021 Shift Register Parallel In Serial Out

[anotherdude]

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?

[stj]

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.

[keeney123]

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?

[stj]

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?

just an error in the datasheet, they got the columns the wrong way around.

[anotherdude]

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.

Thanks, so that one from CPC will do fine?

[stj]

Re: NES Controller 4021 Shift Register Parallel In Serial Out

yes

[anotherdude]

Re: NES Controller 4021 Shift Register Parallel In Serial Out

yes

thanks for your help

[anotherdude]

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