8051 + eprom

Discussion in 'Embedded Systems and Microcontrollers' started by tom123, Aug 20, 2008.

  1. tom123

    Thread Starter New Member

    Sep 30, 2006
    Can anybody tell me how to connect an EPROM to a 8051 to expand its memory.

    I would like a circuit diagram and an explanation of how it woks.

  2. beenthere

    Retired Moderator

    Apr 20, 2004
    Using Google will bring up the information you need. You will need to find the data sheet on the 8051 and also the EPROM (there are many different EPROM's). Both data sheets will have all the information you need.

    There are also numerous 8051 sites which have additional information.
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    I am going to respond to your message here in the forum.

    You haven't got the relationship of EPROM to microcontroller quite right. An EPROM is a device that may be filled with data or program code to execute. It shares the same data bus as any other memory. Its Chip Select signal that enables it to function is only active in the range of memory space assigned to it - that is a job for you, to make up an address decode circuit to enable the various memory devices and any I/O chips.

    There are no Cliff's Notes on this stuff. It is overwhelming the first time into it, but reading and thoroughly understanding the data sheets is about the only way to put this stuff together.

    Then you get to write the code to make it work....
  4. Arm_n_Legs

    AAC Fanatic!

    Mar 7, 2007
    This very old dated manual has some good notes and sample connection diagram.

    However, I would rather choose a 8051 with embedded flash memory. Using 8051 in the extended mode (external memory mode) use up two ports of the 8051 leaving few I/Os.