Connect with us

divide-by-5 and divide-by-10?

Discussion in 'Electronic Basics' started by Kay, Aug 11, 2003.

Scroll to continue with content
  1. Kay

    Kay Guest

    Hi, All:

    Is there any way to hook up a divide-by-5 and divide-by-10 counter using a
    binary counter? I was using 74LS90 to do this before, but it stopped
    working. I am now thinking to transfer to HCT family but I can't find any
    decade/binary counter in HCT family, only binary counter is available, not
    sure why.

    thanks,
    -Kay
     
  2. -----------
    The only reason it "stopped working" is because the way YOU used it
    blew it up, which you'll do with ANY counter handed to you. Instead
    of looking for a different counter you should look for a different
    designer, or improve your skills by finding out what you did wrong!

    -Steve
     
  3. I just pulled out a databook, and it shows there were (I have no
    idea how available they still are) 74HC390s, which are dual decade
    counters about the equivalent of two 7490s.

    Decade counters are made up of binary counters with some sort of
    feedback to reset them early, so look in one of Don Lancaster's cookbooks
    and you're bound to see how it's done, or even look at the datasheet
    for the 7490.

    What you are doing defines the end results. In the old days,
    7490s were pretty common, in two places. One was merely to divide
    the input signal by ten, and you only needed divide by ten output.
    Other times they'd be in counters of some sort, and you actually
    needed the BCD outputs, to drive BCD to decimal or seven segment
    decoders. I suspect if you only need to divide something by
    ten, you have a lot more leeway than if you actually need BCD
    output. For instance, there was a 74HC4017.

    And I am just looking at an older Motorola databook. Likely
    there are other possibilities, if one looks.

    Michael
     
  4. dan williams

    dan williams Guest

    Steve!

    a little less blame, a little more help...

    Kay, what ARE you hooking the '90 up to?

    dan

    --
    Dan Williams, Owner
    Electronic Device Services
    (604) 741 8431
    RR8 855 Oshea rd
    Gibsons BC Canada
    V0N 1V8
     
  5. Suitably programmed PIC12F6xx?
    JDG
     
  6. Hi,

    The 74HC390 is a dual x2 plus x5 counter (there probably is a
    74HCT version as well.) I designed one into a divide by 5,000
    chain just recently. Incidently, a good chip for dividing by
    awkward numbers is the 74HCT40103 which can be preset for any
    count from 2 to 255 and clocks up to around 20MHz.


    Cheers - Joe
     
  7. Kay

    Kay Guest

    Thank you all for pointing out things...I am trying to synchronize 2
    devices. I don't know their internal circuits. The only thing I know is that
    they are both TTL compatible...74LS90 worked fine for us until recently it
    stopped working. I am now on the west coast and only had very basic
    electronics. The summer student who is working on this on the east coast
    hasn't had any electronics yet. I've ordered more 74LS90 online but not sure
    if they can arrive on time. We have some binary counters at hand (74LS93
    (x2), 74LS05, 74LS04, 74HC163, 74HCT161E) that's why I want to use binary
    counters to build a divide-by-5&divide-by-10 circuit. I just figured out how
    74LS90 works last night. Now I need to see if I can adapt a binary counter
    easily to that...That said, 74LS90 has very limited input voltage range.
    I've had static shocks in the lab before so I thought we somehow burnt the
    chip. That's why I want a more noise-endurable TTL-compatible family
    now...Again, I don't have any electronics textbook at hand right now, and I
    only had very basic electronics at school. So the questions I asked might
    sound silly.

    thanks again,
    -Kay
     
  8. Dennis

    Dennis Guest

    I've used the 7490. It works best as an even modulo type
    of counter. It can be set as a divide by 5,or 3 , but
    the duty cycle won't be exactly symmetrical. For me
    that was important for my app, it may not be for yours.

    good luck,

    Dennis
     
  9. dan williams

    dan williams Guest

    it almost sounds like your mixing families that dont want to be mixed...
    go to the manufacturers sites and look at the input and output
    threashold voltages for the chips your interfacing. you may need pull
    up/down resistors.

    dan

    --
    Dan Williams, Owner
    Electronic Device Services
    (604) 741 8431
    RR8 855 Oshea rd
    Gibsons BC Canada
    V0N 1V8
     
  10. Active8

    Active8 Guest

    yeah. those HCs aren't going to agree with their TTL cousins. that's
    what xCTs are for.

    mike
     
  11. Fred Bloggs

    Fred Bloggs Guest

    If you have to use the LS93 and the LS05 is available then you can do
    something like this:

    Please view in a fixed-width font such as Courier.

    DIVIDE BY 5

    CLK>-----------------------+----------+
    TTL | |
    IN inverters --- ---
    74LS05 \ / \ /
    O O
    | |
    | |
    | | 1k
    CLK +------------/\/\---+-o Vcc
    --- <-+ +--------+--+ | | |
    5 | | | | | +--------------+
    | | | | | | | |
    | | +-RO-RO--CLK--CLK-+ | |
    | | | 1 2 B A | | |
    | | | | | |
    | | | 74LS93 | | |
    | | | | | |
    | | +-QD--QC--QB---QA-+ | |
    | | | | | | |
    +---|-------|---+ +---|<|----+ |
    | | '4148 | 680 |
    | +-----------|<|----+--/\/\--+
    | 1k | |
    +-----------+--/\/\--------|--------+
    | | | |
    | | --+-- |
    | | '3904 / \ |
    | | +----+-e c-----+
    | | | | |
    o --- --- | 220 |
    / \ \ / \ / +--/\/\-o gnd |
    --- O O |
    | 1000p | | 1k |
    +----||-----+----+------------/\/\--+
    | |
    | 680 |
    +-----------------------------/\/\--+




    DIVIDE BY 10

    CLK>----------------------------+-----+
    TTL | |
    IN inverters --- ---
    74LS05 \ / \ /
    O O
    | | 1k
    CLK +-------/\/\---+-o Vcc
    --- <-+ +--------+--+ | | |
    10 | | | | +----|---------+ |
    | | | | | | | | |
    | | +-RO-RO--CLK--CLK-+ | | |
    | | | 1 2 B A | | | |
    | | | | | | |
    | | | 74LS93 | | | |
    | | | | | | |
    | | +-QD--QC--QB---QA-+ | | |
    | | | | | | | | |
    | | | | | +---------+ |
    | | | | | | |
    +---|-------|---+ +---|<|----+ |
    | | '4148 | 680 |
    | +-----------|<|----+--/\/\--+
    | 1k | |
    +-----------+--/\/\--------|--------+
    | | | |
    | | --+-- |
    | | '3904 / \ |
    | | +----+-e c-----+
    | | | | |
    o --- --- | 220 |
    / \ \ / \ / +--/\/\-o gnd |
    --- O O |
    | 1000p | | 1k |
    +----||-----+----+------------/\/\--+
    | |
    | 680 |
    +-----------------------------/\/\--+



    DIVIDE BY 5 AND 10

    CLK>-----------------------+----------+
    TTL | |
    IN inverters --- ---
    74LS05 \ / \ /
    O O
    | |
    | |
    | | 1k
    +------------/\/\---+-o Vcc
    +--------+--+ | | |
    | | | | +--------------+
    | | | | | | |
    | +-RO-RO--CLK--CLK-+ | |
    | | 1 2 B A | | |
    | | | | |
    | | 74LS93 | | |
    | | | | |
    | +-QD--QC--QB---QA-+ | |
    | | | | | |
    +---|-------|---+ +---|<|----+ |
    | | | '4148 | 680 |
    | | +-----------|<|----+--/\/\--+
    | | 1k | |
    | +-----------+--/\/\--------|--------+
    | | | | |
    | | | --+-- |
    | | | '3904 / \ |
    | | | +----+-e c-----+
    | | | | | |
    | o --- --- | 220 |
    | / \ \ / \ / +--/\/\-o gnd |
    | --- O O |
    | | 1000p | | 1k |
    | +----||-----+----+------------/\/\--+
    --- | |
    \ / | 680 |
    O +-----------------------------/\/\--+
    | |
    | 1k |
    +--------------------------+------/\/\--+
    | |
    | +-----+--+----+ |
    | | | | | |
    | | +-RO-RO--CLK--CLK-+
    | --- | 1 2 B A |
    | gnd | |
    | | 74LS93 |
    | | |
    | +-QD--QC--QB---QA-+
    | |
    | |
    \|/ \|/

    CLK CLK
    --- ---
    5 10



    DIVIDE BY 5 OR 10

    CLK>----------------------------+-----+
    TTL | |
    IN inverters --- ---
    74LS05 \ / \ /
    O O
    | | 1k
    +--+-------/\/\---+-o Vcc
    |5 | | |
    SW o | | |
    o | | |
    CLK <-+ +--------+--+ |\o------------+ |
    OUT | | | | | 10 | | | |
    | | | | | | | | |
    | | +-RO-RO--CLK--CLK-+ | | |
    | | | 1 2 B A | | | |
    | | | | | | |
    | | | 74LS93 | | | |
    | | | | | | |
    | | +-QD--QC--QB---QA-+ | | |
    | | | | | | | | |
    | | | | | +---------+ |
    | | | | | | |
    +---|-------|---+ +---|<|----+ |
    | | '4148 | 680 |
    | +-----------|<|----+--/\/\--+
    | 1k | |
    +-----------+--/\/\--------|--------+
    | | | |
    | | --+-- |
    | | '3904 / \ |
    | | +----+-e c-----+
    | | | | |
    o --- --- | 220 |
    / \ \ / \ / +--/\/\-o gnd |
    --- O O |
    | 1000p | | 1k |
    +----||-----+----+------------/\/\--+
    | |
    | 680 |
    +-----------------------------/\/\--+
     
  12. Fred Bloggs

    Fred Bloggs Guest

    Revise that simultaneous divide by 10 and 5 like so to line up the edges:

    Please view in a fixed-width font such as Courier.


    DIVIDE BY 5 AND 10

    CLK>-----------------------+----------+
    TTL | |
    IN inverters --- ---
    74LS05 \ / \ /
    O O
    | |
    | |
    | | 1k
    +------------/\/\---+-o Vcc
    +--------+--+ | | |
    | | | | +--------------+
    | | | | | | |
    | +-RO-RO--CLK--CLK-+ | |
    | | 1 2 B A | | |
    | | | | |
    | | 74LS93 | | |
    | | | | |
    | +-QD--QC--QB---QA-+ | |
    | | | | | |
    +---|-------|---+ +---|<|----+ |
    | | | '4148 | 680 |
    | | +-----------|<|----+--/\/\--+
    | | 1k | |
    | +-----------+--/\/\--------|--------+
    | | | | |
    | | | --+-- |
    | | | '3904 / \ |
    | | | +----+-e c-----+
    | | | | | |
    | o --- --- | 220 |
    | / \ \ / \ / +--/\/\-o gnd |
    | --- O O |
    | | 1000p | | 1k |
    | +----||-----+----+------------/\/\--+
    | | |
    | | 680 |
    | +-----------------------------/\/\--+
    | |
    | 1k |
    +---|---------------------------------/\/\--+
    | |
    | +--------------------------+
    | | |
    | --- +-----+--+----+ |
    | \ / | | | | |
    | O | +-RO-RO--CLK--CLK-+
    | | --- | 1 2 B A |
    +---+ gnd | |
    | | 74LS93 |
    | | |
    | +-QD--QC--QB---QA-+
    | |
    | |
    \|/ \|/

    CLK CLK
    --- ---
    5 10
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-