8255 equivalent?

Discussion in 'General Electronics Chat' started by mik3ca, Mar 6, 2008.

  1. mik3ca

    Thread Starter Active Member

    Feb 11, 2007
    189
    0
    an 82c55 is a chip that is useful to me, but the problem with it is that it has too much functionality.

    What I want is the same functionality as at least 2 bytes of static ram and some functionality of the 8255. The chip needs to have 24 latchable I/O pins, one or two bits that determine which way the data transfers, and at least two bits that determine which group of 8 pins are being written to or read from.

    So basically, I'm looking for an 82c55 equivalent, but with only mode 0 of the 82c55, and without having to program the chip in a special way to use it.

    Does anyone know of any such chip?

    I want to avoid using multiple 74xx373's and 74xx573's.
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,145
    1,791
    Those chips with a parallel bus are increasingly anachronistic.

    Here is a chip from Maxim with the I/O pin count on an SPI bus
    http://datasheets.maxim-ic.com/en/ds/MAX7301.pdf

    For a little while longer ST Microelectronics may continue to make the PSD311/312/313 family. They have OTP ROM, RAM, and 16 port pins.
    http://www.st.com/stonline/products/literature/ds/7829/psd311.pdf

    Last option is an FPGA with RAM. You can pretty much roll anything you want. As to your specific requirements I think you're pretty much outta luck. Sorry 'bout that.
     
  3. mrmeval

    Distinguished Member

    Jun 30, 2006
    833
    2
    Look for a company that provides an 82C55 core for their FPGA or CPLD modify that core to fit or design it from scratch.

    The PSD is nice but companies are obsoleting them and doing so *fast*.
     
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