What is the job of that IC "74HCT245"?

Discussion in 'General Electronics Chat' started by buffon2009, Aug 28, 2012.

  1. buffon2009

    Thread Starter New Member

    Dec 7, 2011
    hi everyone

    i wanna know What is the job of that IC "74HCT245"? as in see it in schematics of some device

    when i downloaded the database, i found that its "Octal Bus Transceiver" So what meant by that?

    Thank you in advance
  2. t06afre

    AAC Fanatic!

    May 11, 2009
    What schematic;) The function will depend on how it is used. I used it in 8 bit micro processor applications. As a buffer between the the processor and the other units on the data bus. In those days the micro processor could only drive a few TTL loads. But the 74xx245 was able to drive much higher number of TTL loads. And hence it was used as a bidirectional buffer
    Try google and bus transceiver for more info
  3. absf

    Senior Member

    Dec 29, 2010
    Yes, t06afre is right. You can think of it as 2x 74xx244 connected back to back, with a direction control logic. When DIR is H, signals flow from left to right and vice versa when DIR is L.

  4. Papabravo


    Feb 24, 2006
    Octal = Eight(8)
    Bus = Data Bus
    Transceiver = Moves data in both directions depending on control signals
  5. dataman19


    Dec 26, 2009
    Octal bus transciever::::::
    This means it buffers eight data lines...
    But also passes data both ways (hence transceiver).
    It also has an enable pin so that it can turn on and off (hence it can be used to completely isolate data buss segments (which is what i normally use them for more than anything)...
    Yea - I know someone will chime in that you need logic decode circuitry and all that stff,,, yadda,,,, yadda.....
    By utilizing Bus Tranceivers you are able to isolate the data lines to say an I/O or Just a "sensor" or "drive" controller.
    If you want to get technical, a 3-state Octal bus would give you the ability to handle more than one I/O ports with one device (assuming the data or address is 8-bits) - but the beauty is that you can use two for 16.... or three for 24... or four for 32... etc (assuming you have a circuit board the size of you dining room table....
    But seriously...everyone is right: Its a handy little tool in MicroController Development. I wouldn't leave the electron shack without one (or two,,, or three)...
    Phoenix, AZ