AT89S8052 to RAM chip interface

Discussion in 'General Electronics Chat' started by cmartinez, Jan 5, 2016.

  1. cmartinez

    Thread Starter AAC Fanatic!

    Jan 17, 2007
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    I've been working all day in a design of mine involving an AT89S8052 and now I've come to the point in which I have to interface it to a ram memory chip (I've attached its datasheet)

    My question is, will the MCU be able to drive its pins directly when operated in SPI mode?
    I'm asking because this MCU in particular has bi-directional pins, with weak pull ups. And nowhere in the memory chip's datasheet does it say what sort of inputs and outputs it has.

    So I'm assuming that it has standard high-impedance inputs, and push-pull outputs. If that's the case, there shouldn't be a problem connecting it directly to the aforementioned MCU. Or should it?
     
  2. Papabravo

    Expert

    Feb 24, 2006
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    Ports 1, 2, and 3 have outputs that will work with the RAM chip just fine. Port 0 as you know has open drain outputs which would require an external pullup.
     
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  3. cmartinez

    Thread Starter AAC Fanatic!

    Jan 17, 2007
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    You've just confirmed what I had already guessed. (the operative word being guessed)
    Now that you've clarified it, I feel a lot more confident now. Thanks again!
     
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