Thread Starter

RipX

Joined Mar 29, 2023
4
Hi everyone,

I am getting ready to build a frequency divider board for a Z80 game console project. I have a 32MHz active crystal oscillator and want to divide down this to produce the following frequencies that will be used across varying components of the project:

  • 32 MHz
  • 16 MHz
  • 8 MHz
  • 4 MHz
  • 2 MHz
  • 1 MHz

I originally thought that I would be able to use a ripple counter such as the CD4040BE however the IC doesn't support such high frequencies as 32 MHz (The project is powered at 5V also) so I'm looking for an alternative. One caveat is that the project is designed to make use of few and inexpensive parts as it's aimed at amateurs as a hobby project. I suppose that I could combine the CD4040BE for the lower frequencies if I'm able to half the frequency at the higher frequencies.

Many thanks,
RipX
 

MrChips

Joined Oct 2, 2009
31,092
74xx374 is intended to be used as an 8-bit latch register. This is not want you need.

What you need are individual D-type or J-K flip-flops, or binary counters such as 74xx161, 74xx163, 74xx191, 74xx193.

Here is how you would use 74xx74 as divide-by-2 counters.

1680105028936.png
 

Thread Starter

RipX

Joined Mar 29, 2023
4
74xx374 is intended to be used as an 8-bit latch register. This is not want you need.

What you need are individual D-type or J-K flip-flops, or binary counters such as 74xx161, 74xx163, 74xx191, 74xx193.

Here is how you would use 74xx74 as divide-by-2 counters.

View attachment 290992
Got ya! I'll see if I can find any of those in a DIP package. Thank you
 

Ian0

Joined Aug 7, 2020
10,277
If you don't need the intermediate outputs to be synchronous, you could use a 74HC4024 or 74HC4040 - They have a guaranteed minimum frequency of about 32MHz at 5V, and a typical value of 80MHz
 
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