keyboard interface

Discussion in 'Embedded Systems and Microcontrollers' started by alagammaik, Mar 5, 2007.

  1. alagammaik

    Thread Starter New Member

    Mar 5, 2007
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    Want a simple circuit to interface 8279 to 8051
     
  2. Dave

    Retired Moderator

    Nov 17, 2003
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    Please read and provide more specific details. It is difficult to be of any help when the original question is so open-ended.

    Dave
     
  3. Papabravo

    Expert

    Feb 24, 2006
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    There is no interface. You connect the pins with the same name together. There is no real reason to use such a chip since it is an obsolete 40-pin gunboat whose functions can easily be accomplished with the microcontroller alone. Why would you want such a clunky solution?
     
  4. Dave

    Retired Moderator

    Nov 17, 2003
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    One would assume it is part of a academic course where it is common to use cheap and freely available (often obsolete) components. Apart from knowing what an interface is and what 8279's and 8052's are, I am still confused as to OP query. The ol' simple plug-and-play interface is always the best!

    Dave
     
  5. Papabravo

    Expert

    Feb 24, 2006
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    I see. Well the 8279 has an 8 pin data bus, and the 8051 has an 8 pin data bus on Port 0. I would connect these two data busses together for starters. You need to figure out how to generate a chip select and a read strobe and a write strobe. Hint look at P3.6 and P3.7 in the 8051 datasheet. These signals are activated by only one instruction in the 8051 instruction set. Read the datasheet, tell me which instruction you would use to generate RD* and WR* on an 8051, and I'll tell you more of the story.

    Since both chips came from Intel at the dawn of uP time I'd be surprised if you couldn't just connect plug and play pin to plug and play pin.
     
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