Buying shift registers - help

Discussion in 'General Electronics Chat' started by Captain E, Jul 2, 2015.

  1. Captain E

    Thread Starter Member

    Jun 16, 2015
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    Oy!
    I'm going to buy a few shift registers to get more inputs and outputs for my Arduino Uno, but I'm kinda confused on everthing about the different types. Operating them isn't the problem but all the different types are.

    Q: Is there any shift register which can give the arduino BOTH more inputs and outputs at the same time?

    If there is any, what is that type called?
    If there is none, I guess every shift register is either giving inputs or outputs? In this case, what is the two types called?

    I dont want to go too deep in all the types, I just want to know which type is the best for me, buy them, and learn how to use just them :3

    Thanks!
     
  2. OBW0549

    Well-Known Member

    Mar 2, 2015
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    A 74HC595 will give you 8 bits of output; a 74HC597 will give you 8 bits of input.
     
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  3. Captain E

    Thread Starter Member

    Jun 16, 2015
    81
    6
    Thanks for the reply.
    I can't buy these exact registers at my local shops, however there are a lot of others I can choose from, but I'm not fully sure which are like the ones you provided, and dont want to take a chance.

    Is there not any certain types that does what I need? For example serial-in serial-out (SISO) that I can look for at my shop?
     
  4. OBW0549

    Well-Known Member

    Mar 2, 2015
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    absf likes this.
  5. Captain E

    Thread Starter Member

    Jun 16, 2015
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    They carry parts from microship.com, but not those two products exactly :/

    After like 15 min of browsing my local store's sortiment, I actually found a 74HC595. (it didn't show up by searching earlier, but I just found it randomly)
    I've decided to use this one as a extra outputs provider, and use the Arduino pins I have left for inputs. (for now, until I go deeper about IC's)

    Thanks for the help, OBW0549! :D
     
  6. OBW0549

    Well-Known Member

    Mar 2, 2015
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    You're welcome!
     
  7. ian field

    Distinguished Member

    Oct 27, 2012
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    Just a guess - but you probably want to narrow it down to the arrangement of serial and parallel.

    If you've got a load of things happening side by side, you probably want a parallel in - serial out, so you can capture all those events in parallel and serial clock them into a single pin.

    For output then; you'd need a serial in - parallel out register that you can serial clock a string of bits into, and then present them as logic levels on a parallel row of pins.

    Next you need to chose how many stages your shift registers will have, 8 stages can hold 8 bits or a byte, if you're programming in 16 bits or more; you can look for registers that long, or cascade 8 bit ones to carry the word length you use.

    The rest is choosing a family from TTL or CMOS that can handle the speed, output sink or supply spec.
     
  8. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    There are I2C expander parts that can be wither inputs or outputs in one chip.

    ak
     
  9. Captain E

    Thread Starter Member

    Jun 16, 2015
    81
    6
    Great information, thank you :D

    OoooH! This saves me money, space on the circuit and work :D Also found many of those at my local store :D
    Going to buy this tomorrow instead on my shopping route :3




    Thanks for the help!
     
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