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Confused now about 74HC154 — Parallax Forums

Confused now about 74HC154

davidsdavids Posts: 64
edited 2005-05-16 13:46 in BASIC Stamp
If I don't use shiftin/out or serin/out.· How do I change the·input/output of the pins of·74HC154, can someone tell me how this commuication works through the 4 binary inputs.·An example of·code to use·with this chip would be fab.

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Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-05-05 02:16
    Hello,

    ·· The 74HC154 is a 4-to-16 line decoder, it's not bi-directional.· A 4-bit address placed on the inputs will select 1 of 16 possible outputs (Active LOW).·· You can't use it the other way around, although there is a reverse operation version of this chip (Different part #).


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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-05-05 02:38
    The 74HC154 has four inputs (A0..A3) and 16 outputs (Y0..Y15).· You set the pins on the inputs to a binary value and the corresponding output pin will go low (assuming E0 and E1 are low).· It's in the spec sheet ... have you checked it out?

    http://www.semiconductors.philips.com/acrobat_download/datasheets/74HC_HCT154_5.pdf

    Connect four Stamp pins to the inputs.· Hint: Use the nibble alignments (P0..P3, P4..P7, P8..P11, or P12..P15).· If you used P0..P3, for example, you could do this:

    Setup:
    · DIRA = %1111··············· ' make P0..P3 outputs

    Main:
    · FOR OUTA = %0000 TO %1111
    ··· PAUSE 1000
    · NEXT
    · GOTO Main

    This will make the outputs on the 154 go on in order for one second.

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    Jon Williams
    Applications Engineer, Parallax
    Dallas, TX· USA
    74HC154.gif
    570 x 687 - 6K
  • Beau SchwabeBeau Schwabe Posts: 6,557
    edited 2005-05-05 03:09
    If you want bi-directional, the 4067B is a 16 channel multiplexer/demultiplexer.

    4067B.pdf

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    Beau Schwabe - Mask Designer III

    National Semiconductor Corporation
    Latest Company News
    (Communication Interface Division)
    500 Pinnacle Court, Suite 525
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  • davidsdavids Posts: 64
    edited 2005-05-05 03:33
    Thanks all for sorting out that that problem, I think I look at the 4067b.
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-05-05 03:46
    What problem are you attempting to solve?

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    Jon Williams
    Applications Engineer, Parallax
    Dallas, TX· USA
  • davidsdavids Posts: 64
    edited 2005-05-05 07:09
    At the momment I'm messing around with different devices Such as multiplexers, eproms, servos, motors, senses. just to get a better understanding how they all can be used with Basic Stamps.
    I have a question about the serin/out command demo. It states that the bs2,bse and bspe can talk to each other, and that the bs2sx and bs2p talk, but I tried to use a BS2p and a BS2e. I haven't really looked at solving it as of yet. PLS help me with hints
  • davidsdavids Posts: 64
    edited 2005-05-05 07:12
    I understand people interested in BASIC STAMP can do Courses to help, are there any available in Australia.
  • Bruce BatesBruce Bates Posts: 3,045
    edited 2005-05-05 07:35
    Davids -

    Any Stamp can "talk" to any other Stamp, presuming the baud rates are appropriate, and the physcial connections are made in a proper manner. So too, any Stamp can talk to a PC, and visa versa presuming the same as above.

    The PBASIC Manual has lots of examples, and the Help File has additional information. Other than that, your question is a bit to broad to be answered. If you have specific questions along with details, help is certainly available here.

    Regards,

    Bruce Bates
  • davidsdavids Posts: 64
    edited 2005-05-16 12:23
    OK ONE MORE TIME JUST IN CASE YOU MISSED THE QUESTION! CAN i JOY A GROUP OF PEOPLE INWHICH BASIC STAMP IS EXPLAINED TO BEGINNERS(A STAMP CLASS)???????? IN AUSTRALIA.

    YOU KNOW /BBQ /DOWNUNDER/ BIG ROCK/ THE POSSUM/ AIRFARE USA to AUS.
    AUS TO USA
    THE QEUSTION AS ABOVE is REALLY simply NEEDS ONE ANSWER Y/N
  • Lee HarkerLee Harker Posts: 104
    edited 2005-05-16 13:36
    David,
    Just a little advise about getting FREE help from a group of very knowledgable folks. Be patient and humble. You start your questions admitting to have done very little research of your own (data sheets are very easy to find) and then get beligerent when the FREE info doesn't come fast enough. The Parallax web site has a plethera of info for beginners you just have to take the time to read a bit.
    And yes I belive most everyone that frequents this forum is well aware of where Australia can be found on a map. I was under the impression the Aussies were a little more cordial folk.
    The lecture light has been turned back off.

    Lee
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-05-16 13:46
    Forum guidelines suggest that you start a new thread when you have a change of topic.· Perhaps a post in the Sandbox forum about clubs or groups in Australia would be your best bet.· And yes, there are lots of BASIC Stamp users down under -- whether any have organized into a group ... I don't know.
    davids said...
    OK ONE MORE TIME JUST IN CASE YOU MISSED THE QUESTION! CAN i JOY A GROUP OF PEOPLE INWHICH BASIC STAMP IS EXPLAINED TO BEGINNERS(A STAMP CLASS)???????? IN AUSTRALIA.
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    Jon Williams
    Applications Engineer, Parallax
    Dallas, TX· USA
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