Looking for a decade counter -or- divider ? (2023 Update)

Decade counter: I am looking for a decade counter, I found some on-line like the 4017 and 74HC[T]390. But I am now sure any of those are what I want. At my previous job we use to have quad decade counters in one chip available. That has been a few years ago and not sure where to look now. What I want to be able to do is tie at least two of them end to end and get a divider of 10 and 100. Maybe the terminology is wrong and I should be looking for a divider ?

Any help is appreciated. Thanks

Reply to
Sid 03
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If all you need to do is divide by 10 and 100 look at a 7490. It has 2 sections as I recall. One divides by 2 and the other by 5 so you hook them up in series. Usually the divide by 2 is the last so you get a better transistion . YOu can put 2 in series to divide by 100.

Reply to
Ralph Mowery

Ralph Mowery schrieb:

For dividing by 100 one needs just a single 74x390 which contains two divide-by-10 counters.

HTH

Reinhard

Reply to
Reinhard Zwirner

HCT390 should work. It's a dual ripple counter.

Maybe use a schmitt gate in front to get a clean clock, depending on what you want to count.

Reply to
jlarkin

On a sunny day (Tue, 25 Jan 2022 08:51:40 -0800 (PST)) it happened Sid 03 snipped-for-privacy@gmail.com wrote in snipped-for-privacy@googlegroups.com:

2 x 74[HCT]90 in series will do that, gives you BCD output too.
Reply to
Jan Panteltje

So either the 4017 or the 390 will do the job, but in either scenario I will need 2 chips ? Is there a chip out there that will do it all in one chip ? Thanks

Reply to
Sid 03

The 74[[HC]T]390 had two decade counters, when the two are combined it can divide by 10 and at the same time by 100.

Isn't that what you want? Or do you want to divide by 10, 100, 1000 and 10000 (the quad case)?

Arie

Reply to
Arie de Muijnck

Even years ago, 'decade' was just a special case of counter, there's many 16-bit timer/counters that will handle /10, /100, /1000, /10000 easily, and low-end controllers typically have several such as onboard peripherals. AT89C55 has three, in addition to compute and I/O resources to use them.

Do you accept output synchronous with a CPU clock? Is this for some UHF divider purpose? There's lots of hardware not sold as 'counter' that will do the task or useful parts of it, just as there's lots of A to D converters that don't come with the ADC label.

Reply to
whit3rd

I seem to remember a triple or quad with muliplexed BCD output, but IIRC they stopped making them last century.

4518 is a dual synchronous counter with individual BCD outputs, the "Q2" or "Q3" outputs will give divide-by 10 but not at 50% duty cycle. 4518 variants are still available from TI
Reply to
Jasen Betts

Interesil used to make frequency counter chips like that, and AD actually still sells the ICM7217 four-digit decade counter. Of course it's $21 and has muxed 7-segment outputs, but hey, it's a quad decade counter. ;)

Cheers

Phil Hobbs

Reply to
Phil Hobbs

I remembered an 8 bit counter with a writable latch so one could make it divide by any 8 bit value but it took looking at an old library disk to recall its name, it was 74LS592... I must have used it as a baud rate divider at some point or something, 30+ years ago. I knew I had used it but can't remember for what purpose and on which board. Looks like it never got made as HC/HCT though, probably no longer available. But it must have been nice, writable via an 8 bit bus in a DIP16 (I have drawn the part I found only in dip16, looks like I never used it in so-16).

Reply to
Dimiter_Popoff

Tom Van Baak published a list of PIC counters that give various ratios, such as 1e7 (10MHz to 1Hz) with jitter under 2ps. Here is a list with source code:

picDIV -- Single Chip Frequency Divider

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PIC divider jitter measurement
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He also posted a different version to time events:

picPET -- Precision Event Timer, more versions

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Reply to
Arnie Dwyer

On a sunny day (Sat, 29 Jan 2022 00:27:22 -0000 (UTC)) it happened Arnie Dwyer snipped-for-privacy@not.com wrote in <XnsAE2DC5EADE5E9idtokenpost@144.76.35.252>:

Sure, using Mircochip PICs much is possible here my frequency counter in an RS232 connector, powered from the RS232 DTR::

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But then he needs a PIC programmer etc...

I am sure an ebay search will get you many cheap frequency counters too.

Reply to
Jan Panteltje

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