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10hr Timer Design Help

Discussion in 'Electronic Basics' started by BM, Aug 12, 2003.

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  1. BM

    BM Guest

    Can anyone help point me in the right direction?

    I want to make a timer circuit using discreet components (i.e. no pics or
    stamps or inputs from a PC) that will count from 0 when it turns on up to
    9hrs 59mins 59secs. I also want to display the hrs, mins and secs via
    7-segment displays. In addition, I would like to be able to freeze and
    display the clocks count at any given moment via a hold button.



    thanks
     
  2. Well, by discrete components, are you saying "no integrated circuits"?
    If you go for a microcircuitry solution, this is trivial and a bit of busy
    work if you use gates and counters. Not hard, mind you, but detailed. If you
    go for a digital counter/multiplexor chip, many function as timer or counter
    devices in HH:MM:SS format.
    If you truly mean discrete components only, be prepared to make a big box
    full of transistors and diodes as you will have to build your own gates and then
    make counters and decoders and drivers. This would be a really complex task and
    cost a lot.

    Cheers!

    Chip Shults
    My robotics, space and CGI web page - http://home.cfl.rr.com/aichip
     
  3. onestone

    onestone Guest

    Why are you intentionally making your life difficult? You want to
    replace one chip and a couple of hours learning with a couple of
    handfuls of chips, days of debugging, and a damn sight more to learn
    than with a micro? A wholly pointless excercise unless the objective is
    to learn how to design logic circuits.

    Al
     
  4. Fred Bloggs

    Fred Bloggs Guest

    It will look something like this:

    The FREEZE may need synchronization- you don't say whether you want just
    the display to freeze while count continues or the count should freeze
    also. The 1Hz timebase can be derived any number of ways like an
    external oscillator or divided mains frequency etc.

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


    BASIC DIVIDE BY 59 COUNTER W/BCD OUTPUT

    (BDB59CW/BO)


    SCHEMATIC
    UNITS TENS
    TO DISPLAY TO DISPLAY
    /------^------\ /------^------\
    | | | | _ UB | | | | _ UE
    | | | +-----| \ | | +--|-----| \
    | | | | | O--+ | | | | | O--+
    VCC +--|--|--|-----|_/ | VCC +--|--|--|-----|_/ |
    | | | | | UA 'HCT00| | | | | | UD 'HCT00|
    | +---------------+ | | +---------------+ |
    | | Q0 Q1 Q2 Q3 | | | | Q0 Q1 Q2 Q3 | |
    | | --- | | | | --- | |
    +--| SPE | | +--| SPE | |
    | | | | | |
    | -- | 10K | ___ UC | -- | 10K |
    | MR |-+/\/\-+-\ \ | MR |-+/\/\-+
    CI>-----| TE | | | | O---| TE | | |
    | | | +-/__/ | | | |
    +-|>CLK | | | 'HCT02 | 74HCT163 | | |
    | | 74HCT163 | | +--|---------|>CLK | | |
    | | | | | | | | | |
    PEC>+---| PE | | | | +------| PE | | |
    | | | | | | | | | | | |
    | | | P0 P1 P2 P3 | | | | | | P0 P1 P2 P3 | | |
    | | +---------------+ | | | | +---------------+ | |
    | | | | | | | | | | | | | | | |
    | | +--+--+--+ | | | | +--+--+--+ | |
    | | | | | | | | | |
    | | --- | | | | --- | |
    | | | | | | +--------------------------+
    +-|-------------------|--|--|--+ | ___ UF |
    | | | | +-\ \ |
    | | | | | O-----------------> CO
    CCLK>-+----------------------+ +--------/__/ |
    __ | 'HCT02 |
    MR>-----------------------+---------------------------------+


    SYMBOL


    BDB59CW/BO
    +-----------+ 4
    +-----------+







    10 HOUR DISPLAY TIMER

    FREEZE
    -+- 10K
    +--o o---------+------------------+---/\/\-+-VCC
    | | | |
    --- +---------------+ +--|--------+
    | | | | | S
    START | | +-------------------+ 4 E
    _ | | | -- C C P UNITS|--/--> C
    +--o o---+--|--|------| MR C I E | 4 O
    | NC | | | | L C TENS|--/--> N
    --- | | | | K | D
    | | | | CO | S
    | | | +-----------BDB59CW/BO
    | | | |
    | | +---------------|--+
    | | | | |
    | | | +------------+ |
    | | | | | |
    1Hz CLK-------+---------------+ | |
    | | | | | | | M
    | | | | +-------------------+ 4 I
    | | | | | -- C C P UNITS|--/--> N
    +------------| MR C I E | 4 U
    | | | | | L C TENS|--/--> T
    | | | | | K | E
    | | | | | CO | S
    | | | | +--------+--BDB59CW/BO
    | | | | |
    | | | | | 'HCT00
    | | | +------------|-------| \
    | | | | | O--|
    | | | +-------|_/ |
    | | | |
    | | +------------------+ 'HCT02|
    | | | / /---+
    | +---------------+ +--|---o | |
    | | | | \_\---+
    | | | | H
    | +-------------------+ 4 O
    | | -- C C P UNITS|--/--> U
    +------------| MR C I E | R
    | L C TENS|N/C S
    | K |
    | CO |
    +-----------BDB59CW/BO
    N/C

    OMIT UC, UD, UE, UF
     
  5. Fred Bloggs

    Fred Bloggs Guest

    Add diodes to schematic like so:

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






    BASIC DIVIDE BY 59 COUNTER W/BCD OUTPUT

    (BDB59CW/BO)


    SCHEMATIC
    UNITS TENS
    TO DISPLAY TO DISPLAY
    /------^------\ /------^------\
    | | | | _ UB | | | | _ UE
    | | | +-----| \ | | +--|-----| \
    | | | | | O--+ | | | | | O--+
    VCC +--|--|--|-----|_/ | VCC +--|--|--|-----|_/ |
    | | | | | UA 'HCT00| | | | | | UD 'HCT00|
    | +---------------+ | | +---------------+ |
    | | Q0 Q1 Q2 Q3 | | | | Q0 Q1 Q2 Q3 | |
    | | --- | | | | --- | |
    +--| SPE | | +--| SPE | |
    | | | | | |
    | -- | 10K | ___ UC | -- | 10K |
    | MR |-+/\/\-+-\ \ | MR |-+/\/\-+
    CI>-----| TE | | | | O---| TE | | |
    | | | +-/__/ | | | |
    +-|>CLK | | | 'HCT02 | 74HCT163 | | |
    | | 74HCT163 | | +--|---------|>CLK | | |
    | | | | | | | | | |
    PEC>+---| PE | | | | +------| PE | | |
    | | | | | | | | | | | |
    | | | P0 P1 P2 P3 | | | | | | P0 P1 P2 P3 | | |
    | | +---------------+ | | | | +---------------+ | |
    | | | | | | | | | | | | | | | |
    | | +--+--+--+ | | | | +--+--+--+ | |
    | | | | | | | | | |
    | | --- | | | | --- | |
    | | | | | | +--------------------------+
    +-|-------------------|--|--|--+ | ___ UF |
    | | | | +-\ \ |
    | | | | | O-----------------> CO
    CCLK>-+----------------------+ +--------/__/ |
    __ | 'HCT02 |
    +--|<|-+ |
    | 1N4148 |
    MR>----------------+------------------------|<|-------------+
    1N4148
     
  6. Blake

    Blake Guest

    Sounds like a school project to me.

    Blake
     
  7. Fred Bloggs

    Fred Bloggs Guest

    Parts count works out better with this:

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


    BASIC DIVIDE BY 59 COUNTER W/BCD OUTPUT

    (BDB59CW/BO)


    SCHEMATIC
    UNITS TENS
    TO DISPLAY TO DISPLAY
    /------^------\ /------^------\
    | | | | _ UB | | | | _ UE
    | | | +-------| \ | | +--|-----| \
    | | | | | O--+ | | | | | O----+
    VCC +--|--|--|-------|_/ | VCC +--|--|--|-----|_/ |
    | | | | | 'HCT00| | | | | | 'HCT00 |
    | +--------------UA | | +--------------UD |
    | | Q0 Q1 Q2 Q3 | | | | Q0 Q1 Q2 Q3 | |
    | | --- | | | | --- | |
    +--| SPE | | +--| SPE | UG |
    | | UF | | | 'HCT08 |
    | | 'HCT08 | ___ UC | -- | / |---+
    | -- | / |---+-\ \ | MR |-| | |
    CI>-----| TE MR |-| | | | O---| TE | \__+-+ |
    | | \__+-+ +-/__/ | | +-----+ |
    +-|>CLK | +---+ | 'HCT02 | 74HCT163 | | |
    | | 74HCT163 | | | | | |
    | | | | +--|---------|>CLK | | |
    PEC>+---| PE | | | | +------| PE | | |
    | | | | | | | | | | | |
    | | | P0 P1 P2 P3 | | | | | | P0 P1 P2 P3 | | |
    | | +---------------+ | | | | +---------------+ | |
    | | | | | | | | | | | | | | | |
    | | +--+--+--+ | | | | +--+--+--+ | |
    | | | | | | | | | |
    | | --- | | | | --- | |
    | | | | | | +----------------------------+
    +-|---------------------|--|--|--+ | ___ UF |
    | | | | +-\ \ |
    +-+ | | | | O-----------------> CO
    CCLK>-+----------------------+ +--------/__/ |
    | 'HCT02 |
    | |
    __ | |
    MR>-----------------------+---------------------------------+

    SYMBOL

    BDB59CW/BO
    +-----------+ 4
    +-----------+






    10 HOUR DISPLAY TIMER

    FREEZE +---------------------------------+
    -+- | 1K |
    +--o o---------+------------------+---/\/\-+-VCC
    | | | |
    | \ | | |
    --- 1K +---------------+ +--|--------+
    \ | | | | | S
    START / | | +-------------------+ 4 E
    _ | | | | -- C C P UNITS|--/--> C
    +--o o---+--|--|------| MR C I E | 4 O
    | NC | | | | L C TENS|--/--> N
    --- | | | | K | D
    | | | | CO | S
    | | | +-----------BDB59CW/BO
    | | | |
    | | +---------------|--+
    | | | | |
    | | | +------------+ |
    | | | | | |
    1Hz CLK-------+---------------+ | |
    | | | | | | | M
    | | | | +-------------------+ 4 I
    | | | | | -- C C P UNITS|--/--> N
    +------------| MR C I E | 4 U
    | | | | | L C TENS|--/--> T
    | | | | | K | E
    | | | | | CO | S
    | | | | +--------+--BDB59CW/BO
    | | | | |
    | | | | | 'HCT00
    | | | +------------|-------| \
    | | | | | O--+
    | | | +-------|_/ |
    | | | |
    | | +------------------+ 'HCT00|
    | | | / |---+
    | +---------------+ +--|---o | |
    | | | | \_|---+
    | | | | H
    | +-------------------+ 4 O
    | | -- C C P UNITS|--/--> U
    +------------| MR C I E | R
    | L C TENS|N/C S
    | K |
    | CO |
    +-----------BDB59CW/BOH
    N/C

    Make HOURS counter like so:


    HOURS
    TO DISPLAY
    /------^------\
    | | | | _ UB
    | | | +-------| \
    | | | | | O--+
    VCC +--|--|--|-------|_/ |
    | | | | | 'HCT00|
    | +--------------UA |
    | | Q0 Q1 Q2 Q3 | |
    | | --- | |
    +--| SPE | |
    | | |
    | -- | 10K |
    | MR |---+/\/\-+
    CI>-----| TE | |
    | | |
    +-|>CLK | |
    | | 74HCT163 | |
    | | | |
    PEC>----| PE | |
    | | | |
    | | P0 P1 P2 P3 | |
    | +---------------+ |
    | | | | | |
    | +--+--+--+ |
    | | |
    | --- |
    | |
    | |
    | |
    CCLK>-+ |
    |
    __ 1N4148 |
    MR>---------|<|-----------+
     
  8. Fred Bloggs

    Fred Bloggs Guest

    The circuit below is the most economical in terms of gates required- not
    to mention the count logic is correct:

    IC notation is for 74HCT163 at http://www.ti.com

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


    BASIC DIVIDE BY 60 COUNTER W/BCD OUTPUT

    (BDB60CW/BO)


    SCHEMATIC
    UNITS TENS
    TO DISPLAY TO DISPLAY
    /------^------\ /------^------\
    | | | | | | | |
    | | | | | | | |
    +-------------------------+ +--------------------------+
    | | | | | | | | | | | |
    | | | | | _ UB | | | | | | _ UE |
    | | | | +-----| \ | | | | +--|-----| \ |
    +--|----|--|--|--|-----| O--+ | | | | | | O--+
    | | +--|--|--|-----|_/ | | +--|--|--|-----|_/ |
    | | | | | | 'HCT10| | | | | | 'HCT00|
    | | +--------------UA | | +--------------UD |
    | | | Q0 Q1 Q2 Q3 | | | | Q0 Q1 Q2 Q3 | |
    | | | --- | | | | --- | |
    | +-| SPE | | +--| SPE | |
    | | | | | | |
    | | -- | | ___ UC | -- | |
    | | MR |-+ +-\ \ | MR |-+ |
    CI>+----| TE | | | | O---| TE | | |
    | | | +-/__/ | | | |
    +-|>CLK | | | 'HCT02 | 74HCT163 | | |
    | | 74HCT163 | | +--|---------|>CLK | | |
    | | | | | | | | | |
    PEC>+---| PE | | | | +-----| PE | | |
    | | | | | | | | | | | |
    | | | P0 P1 P2 P3 | | | | | | P0 P1 P2 P3 | | |
    | | +---------------+ | | | | +---------------+ | |
    | | | | | | | | | | | | | | | |
    | | +--+--+--+ | | | | | +-----+-+ | |
    | | | | | | | | | | | |
    | | --- | | | | +---+-----+ --- | |
    | | | | | | | com | |
    +-|-------------------|--|--|---+ | +-----------------+
    | | | | | | |
    | | | | | | __ UF |
    CCLK>-+----------------------+ +---------+--------\ \ |
    | | | O-------> CO
    | +--/__/ |
    | 'HCT02 |
    __ | |
    MR>-----------------------+---------------------------------+



    SYMBOL

    BDB60CW/BO
    +-----------+ 4
    +-----------+





    10 HOUR DISPLAY TIMER

    FREEZE +---------------------------------+
    -+- | 1K |
    +--o o---------+------------------+---/\/\-+-VCC
    | | | | |
    | \ | | |
    --- 1K +---------------+ +--|--------+
    \ | | | | | S
    START / | | +-------------------+ 4 E
    _ | | | | -- C C P UNITS|--/--> C
    +--o o---+--|--|------| MR C I E | 4 O
    | NC | | | | L C TENS|--/--> N
    --- | | | | K | D
    | | | | CO | S
    | | | +-----------BDB60CW/BO
    | | | |
    | | +---------------|--+
    | | | | |
    | | | | |
    | | | | |
    1Hz CLK-------+---------------+ | |
    | | | | | | M
    | | | +-------------------+ 4 I
    | | | | -- C C P UNITS|--/--> N
    +------------| MR C I E | 4 U
    | | | | L C TENS|--/--> T
    | | | | K | E
    | | | | CO | S
    | | | +--------+--BDB60CW/BO
    | | | |
    | | +------------------+
    | | | |
    | +---------------+ | |
    | | | |
    | | | | H
    | +-------------------+ 4 O
    | | -- C C P UNITS|--/--> U
    +------------| MR C I E | R
    | L C TENS|N/C S
    | K |
    | CO |
    +-----------BDB60CW/BOM
    N/C



    HOURS
    TO DISPLAY
    /------^------\
    | | | |
    | | | |
    +-------------------------+
    | | | | | |
    | | | | | _ UB |
    | | | | +-----| \ |
    +--|----|--|--|--|-----| O--+
    | | +--|--|--|-----|_/
    | | | | | | 'HCT10
    | | +--------------UA
    | | | Q0 Q1 Q2 Q3 |
    | | | --- |
    | +-| SPE |
    | | |
    | | -- |
    | | MR |-+
    CI>+----| TE | |
    | | |
    CCLK>----|>CLK | |
    | 74HCT163 | |
    | | |
    PEC>----| PE | |
    | | |
    | P0 P1 P2 P3 | |
    +---------------+ |
    | | | | |
    +--+--+--+ |
    | |
    --- |
    __ |
    MR>-----------------------+
     
  9. Fred Bloggs

    Fred Bloggs Guest

    This one adds an asynchronous FREEZE control using the remaining 2x
    NANDS- action takes effect on inactive negative going clock edge so that
    it is glitch proof:

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






    BASIC DIVIDE BY 60 COUNTER W/BCD OUTPUT

    (BDB60CW/BO)


    SCHEMATIC
    UNITS TENS
    TO DISPLAY TO DISPLAY
    /------^------\ /------^------\
    | | | | | | | |
    | | | | | | | |
    +-------------------------+ +--------------------------+
    | | | | | | | | | | | |
    | | | | | _ UB | | | | | | _ UE |
    | | | | +-----| \ | | | | +--|-----| \ |
    +--|----|--|--|--|-----| O--+ | | | | | | O--+
    | | +--|--|--|-----|_/ | | +--|--|--|-----|_/ |
    | | | | | | 'HCT10| | | | | | 'HCT00|
    | | +--------------UA | | +--------------UD |
    | | | Q0 Q1 Q2 Q3 | | | | Q0 Q1 Q2 Q3 | |
    | | | --- | | | | --- | |
    | +-| SPE | | +--| SPE | |
    | | | | | | |
    | | -- | | ___ UC | -- | |
    | | MR |-+ +-\ \ | MR |-+ |
    CI>+----| TE | | | | O---| TE | | |
    | | | +-/__/ | | | |
    +-|>CLK | | | 'HCT02 | 74HCT163 | | |
    | | 74HCT163 | | +--|---------|>CLK | | |
    | | | | | | | | | |
    PEC>+---| PE | | | | +-----| PE | | |
    | | | | | | | | | | | |
    | | | P0 P1 P2 P3 | | | | | | P0 P1 P2 P3 | | |
    | | +---------------+ | | | | +---------------+ | |
    | | | | | | | | | | | | | | | |
    | | +--+--+--+ | | | | | +-----+-+ | |
    | | | | | | | | | | | |
    | | --- | | | | +---+-----+ --- | |
    | | | | | | | com | |
    +-|-------------------|--|--|---+ | +-----------------+
    | | | | | | |
    | | | | | | __ UF |
    CCLK>-+----------------------+ +---------+--------\ \ |
    | | | O-------> CO
    | +--/__/ |
    | 'HCT02 |
    __ | |
    MR>-----------------------+---------------------------------+



    SYMBOL

    BDB60CW/BO
    +-----------+ 4
    +-----------+




    FREEZE CONTROL SCHEMATIC SYMBOL
    +------+
    | |PEC
    0.1u |FREEZE|->
    com---||--+ | CTL |
    | +------+
    100K | 10K
    +--/\/\--+---/\/\--+ 'HCT00
    | 10K | __
    5V >-+--/\/\-----------------+--------------| \
    | 100K | | | o-+-->PEC
    +--/\/\-+ | | +--|__/ |
    | | | | |
    | | o run +-|--------+
    1Hz | 1000p | | |
    CLK >---|<|---+---||--------o SW | +--------+
    1N4148 | | \ | |
    === | o freeze | 'HCT00 |
    10p | | | __ |
    | | | +----| \ |
    --- | | | o-+
    com +----+--------------|__/







    10 HOUR DISPLAY TIMER



    +------+
    | |PEC
    |FREEZE|->>-----+------------------+
    | CTL | | |
    +------+ +-----|------------------|--------+-VCC
    | | | |
    \ | | |
    1K +---------------+ +--|--------+
    \ | | | | | S
    START / | | +-------------------+ 4 E
    _ | | | | -- C C P UNITS|--/--> C
    +--o o---+--|--|------| MR C I E | 4 O
    | NC | | | | L C TENS|--/--> N
    --- | | | | K | D
    | | | | CO | S
    | | | +-----------BDB60CW/BO
    | | | |
    | | +---------------|--+
    | | | | |
    | | | | |
    | | | | |
    1Hz CLK-------+---------------+ | |
    | | | | | | M
    | | | +-------------------+ 4 I
    | | | | -- C C P UNITS|--/--> N
    +------------| MR C I E | 4 U
    | | | | L C TENS|--/--> T
    | | | | K | E
    | | | | CO | S
    | | | +--------+--BDB60CW/BO
    | | | |
    | | +------------------+
    | | | |
    | +---------------+ | |
    | | | |
    | | | | H
    | +-------------------+ 4 O
    | | -- C C P UNITS|--/--> U
    +------------| MR C I E | R
    | L C TENS|N/C S
    | K |
    | CO |
    +-----------BDB60CW/BOM
    N/C



    HOURS
    TO DISPLAY
    /------^------\
    | | | |
    | | | |
    +-------------------------+
    | | | | | |
    | | | | | _ UB |
    | | | | +-----| \ |
    +--|----|--|--|--|-----| O--+
    | | +--|--|--|-----|_/
    | | | | | | 'HCT10
    | | +--------------UA
    | | | Q0 Q1 Q2 Q3 |
    | | | --- |
    | +-| SPE |
    | | |
    | | -- |
    | | MR |-+
    CI>+----| TE | |
    | | |
    CCLK>----|>CLK | |
    | 74HCT163 | |
    | | |
    PEC>----| PE | |
    | | |
    | P0 P1 P2 P3 | |
    +---------------+ |
    | | | | |
    +--+--+--+ |
    | |
    --- |
    __ |
    MR>-----------------------+
     
  10. I wanted to ask Fred Bloggs but his mail address is suspicious:

    How did you do those ASCII circuts? is there a program that converts
    from another format? or do you place each symbol "by hand" as in the
    old DOS days?


    snip
    snip
     
  11. Fred Bloggs

    Fred Bloggs Guest

    There are modern ASCII art programs that simplify the drawing immensely.
    Now you draw lines by dragging the mouse, and most have copy, paste,
    and move functions on 2-dimensional blocks of characters that are
    selected. In the schematic below I draw one of each component type and
    paste a copy where needed. It is as fun as it is easy these days. There
    was no conversion from a CAD format.
     
  12. JeffM

    JeffM Guest

  13. Rich Webb

    Rich Webb Guest

    There is also a free offering by Andreas Weber at
    http://www.tech-chat.de/ Follow the AACircuit link.

    The site is in German but the "language" is electronics so you'll be
    able to follow it. The program itself is available in German- and
    English-language versions.
     
  14. MAG

    MAG Guest

    If you are still in search of a long duration timer circuit I happened
    across a simple timing circuit.
    The primary ic's used for the timing are 1-555, 1-4017B , 1-4020B.
    The rest of the circuit uses 6-resisters, 1-pot, 1-rotary switch, 4-caps,
    2-diodes , and a transistor.
    If you are still searching drop me a line and I'll look into getting the
    schematic drawn out for you.
    Now you just need a simple display circuit
    MAG
     
  15. bm

    bm Guest

    Thanks for your help Fred. I've build the circuit that you outlined
    and have a couple of follow-up questions.

    First is that I've build the first segment (the seconds part)with the
    74HCT163 and noticed that it is indeed counting up but it is counting
    to 15 and not 9 before resetting. Do I need some sort of 4-bit BIN to
    BCD converter to send to the 7447 to correctly drive the 7-seg leds?
    Would a 74185 work here?

    Also, in regards to the freeze control that you outlined which I've
    build and works very well, would simply putting a switch on the clock
    input (clock connected when switch up and disconnected when the switch
    is down) work as a freeze?

    Thanks again for your help.

    BM
     
  16. Fred Bloggs

    Fred Bloggs Guest

    I have enclosed a new schematic that should clear up the problems. The
    "10 HOUR TIMER" portion has also been changed- the CI input on the
    SECONDS counters cannot be tied to VCC as originally shown- it must be
    joined to the PEC line from the FREEZE CTL as shown- now you can tie
    each individual counter PE to VCC locally at each chip. This make the
    counters freeze if you happen to catch them in the rollover count
    stage-59 etc.

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



    BASIC DIVIDE BY 60 COUNTER W/BCD OUTPUT

    (BDB60CW/BO)


    SCHEMATIC
    UNITS TENS
    TO DISPLAY TO DISPLAY
    /------^------\ /------^------\
    | | | | | | | |
    | | | | | | | |
    +-------------------------+ +--------------------------+
    | | | | | | | | | | | |
    | | | | | _ UB | | | | | | _ UE |
    | | | | +-----| \ | | | | +--|-----| \ |
    +--|----|--|--|--|-----| O--+ | | | | | | O--+
    | | +--|--|--|-----|_/ | | +--|--|--|-----|_/ |
    | | | | | | 'HCT10| | | | | | 'HCT00|
    | | +--------------UA | | +--------------UD |
    | | | Q0 Q1 Q2 Q3 | | | | Q0 Q1 Q2 Q3 | |
    | | | --- | | | | --- | |
    | +-| SPE | | +--| SPE | |
    | | | | | | |
    | | -- | | ___ UC | -- | |
    | | MR |-+ +-\ \ | MR |-+ |
    CI>+----| TE | | | | O---| TE | | |
    | | | +-/__/ | | | |
    +-|>CLK | | | 'HCT02 | 74HCT163 | | |
    | | 74HCT163 | | +--|---------|>CLK | | |
    | | | | | | | | | |
    PEC>+---| PE | | | | +-----| PE | | |
    | | | | | | | | | | | |
    | | | P0 P1 P2 P3 | | | | | | P0 P1 P2 P3 | | |
    | | +---------------+ | | | | +---------------+ | |
    | | | | | | | | | | | | | | | |
    | | +--+--+--+ | | | | | +-----+-+ | |
    | | | | | | | | | | | |
    | | --- | | | | +---+-----+ --- | |
    | | com | | | | | com | |
    +-|-------------------|--|--|---+ | +-----------------+
    | | | | | | |
    | | | | | | __ UF |
    CCLK>-+----------------------+ +---------+--------\ \ |
    | | | O-------> CO
    | +--/__/ |
    | 'HCT02 |
    __ | |
    MR>-----------------------+---------------------------------+



    SYMBOL

    BDB60CW/BO
    +-----------+ 4
    +-----------+




    FREEZE CONTROL SCHEMATIC SYMBOL
    +------+
    | |PEC
    0.1u |FREEZE|->
    com---||--+ | CTL |
    | +------+
    100K | 10K
    +--/\/\--+---/\/\--+ 'HCT00
    | 10K | __
    5V >-+--/\/\-----------------+--------------| \
    | 100K | | | o-+-->PEC
    +--/\/\-+ | | +--|__/ |
    | | | | |
    | | o run +-|--------+
    1Hz | 1000p | | |
    CLK >---|<|---+---||--------o SW | +--------+
    1N4148 | | \ | |
    === | o freeze | 'HCT00 |
    10p | | | __ |
    | | | +----| \ |
    --- | | | o-+
    com +----+--------------|__/







    10 HOUR DISPLAY TIMER



    +------+
    | |PEC
    |FREEZE|->>---------------------+
    | CTL | |
    +------+ +-----+---------------|--+----------VCC
    | | | |
    \ | | |
    1K +---------------+ | |
    \ | | | | | S
    START / | | +-------------------+ 4 E
    _ | | | | -- C C P UNITS|--/--> C
    +--o o---+--|--|------| MR C I E | 4 O
    | NC | | | | L C TENS|--/--> N
    --- | | | | K | D
    | | | | CO | S
    | | | +-----------BDB60CW/BO
    | | | |
    | | +---------------|--+
    | | | | |
    | | | | |
    | | | | |
    1Hz CLK-------+---------------+ | |
    | | | | | | M
    | | | +-------------------+ 4 I
    | | | | -- C C P UNITS|--/--> N
    +------------| MR C I E | 4 U
    | | | | L C TENS|--/--> T
    | | | | K | E
    | | | | CO | S
    | | | +--------+--BDB60CW/BO
    | | | |
    | | +------------------+
    | | | |
    | +---------------+ | |
    | | | |
    | | | | H
    | +-------------------+ 4 O
    | | -- C C P UNITS|--/--> U
    +------------| MR C I E | R
    | L C TENS|N/C S
    | K |
    | CO |
    +-----------BDB60CW/BOM
    N/C



    HOURS
    TO DISPLAY
    /------^------\
    | | | |
    | | | |
    +-------------------------+
    | | | | | |
    | | | | | _ UB |
    | | | | +-----| \ |
    +--|----|--|--|--|-----| O--+
    | | +--|--|--|-----|_/
    | | | | | | 'HCT10
    | | +--------------UA
    | | | Q0 Q1 Q2 Q3 |
    | | | --- |
    | +-| SPE |
    | | |
    | | -- |
    | | MR |-+
    CI>+----| TE | |
    | | |
    CCLK>----|>CLK | |
    | 74HCT163 | |
    | | |
    PEC>----| PE | |
    | | |
    | P0 P1 P2 P3 | |
    +---------------+ |
    | | | | |
    +--+--+--+ |
    | |
    --- |
    __ com |
    MR>-----------------------+
     
  17. bm

    bm Guest

    I think I can but just to be sure, can I mix LS TTLs with HCTs. e.g.
    74HCT163 with 74LS00?

    Thanks Fred. I'll think I'll tear down the circuit I have and rebuild
    it from stratch to make sure I don't have any stupid wirering errors.

    BM
     
  18. Yes, you can mix them. The 'T' in 'HCT' means the cmos device is using TTL
    input thresholds instead of the wider cmos ones. You can always drive a TTL
    input from a cmos output so long as the supplies are the same voltage.

    Hope this helps.
    Dana Frank Raymond
     
  19. Fred Bloggs

    Fred Bloggs Guest

    Yes- that's okay. Change the freeze control like so:

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


    FREEZE CONTROL SCHEMATIC SYMBOL
    +------+
    | |PEC
    |FREEZE|->
    | CTL |
    +------+
    1K
    +--/\/\----------------+ 'LS00
    | 1K | __
    5V >-+--/\/\---------------------+--------------| \
    | 10K | | | o-+-->PEC
    +--/\/\-+ | | +--|__/ |
    | | | | |
    | | o run +-|--------+
    1Hz | 1000p | | |
    CLK >---|<|---+---||----+-------o SW | +--------+
    1N4148 | | | \ | |
    === / | o freeze | 'LS00 |
    10p 10K | | | __ |
    | / | | +----| \ |
    | \ | | | o-+
    +---------+ +----+--------------|__/
    ---
    com

    The whole counter portion is 5x 74xx163's, 1X 74xx00, 1x 74xx02, and 1x
    74xx10. Because the circuit is 100% synchronous and the CLK is a very
    low frequency 1Hz, wire lengths and position are not critical at all
    except for the CLK line. By sure to place a 0.01u bypass across each
    chip between VCC and GND. What construction technique are you using?-
    wirewrap, PCB, point-to-point hardwire and sockets on perfboard? And
    what is the source and circuit for the 1Hz clock?
     
  20. ....and a *bad* one. Ninaries are *strongly* discouraged on text-
    only newsgroups. If you must post a binary do it on a binary
    group (like alt.binaries.schematics.electronic). Posting in WORD
    format also loses you points.

    If you wish to post schematics to a text-only group, may I
    suggest AACircuit.

    Posting binaries to this group is *RUDE*, to say the least!
     
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