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von Neumann like microcontroller

Discussion in 'Embedded' started by John Moore, Jun 7, 2007.

  1. John Moore

    John Moore Guest

    Is there any microcontroller that allows one to map RAM into the program
    address space? In other words, act like a von Neumann based architecture.
     
    John Moore, Jun 7, 2007
    #1
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  2. John Moore

    linnix Guest

    If you mean running program from RAM, then yes. ARMs can do that.
     
    linnix, Jun 7, 2007
    #2
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  3. John Moore

    Coos Haak Guest

    Op Wed, 6 Jun 2007 19:47:36 -0400 schreef John Moore:
    A 80C535 can be configured that the second 32 Kb of both code and data use
    the same addresses. The Dutch Forth Interest Group has a Forth in the first
    half, ROM and can compile and run code and have data in the second half.
    http://www.forth.hccnet.nl/pr-ats.html
     
    Coos Haak, Jun 7, 2007
    #3
  4. Most of them, actually.

    ARM, Z80-based, 68xx, 68xxx, 8086-based, H8, MSP430, NIOS, PPC,
    etc.

    It's a very long list.
     
    Grant Edwards, Jun 7, 2007
    #4
  5. John Moore

    Guy Macon Guest

    The 8051 can do that. The 8051 Bible explains all the details,
    and the technique is easily ported to other Harvard architecture
    microcontrollers that have external RAM and ROM.

    The 8051 Bible Chapter 1: Architectural overview
    http://www.nxp.com/acrobat_download/various/80C51_FAM_ARCH_1.pdf

    The 8051 Bible Chapter 2: Programmers guide and instruction set
    http://www.nxp.com/acrobat_download/various/80C51_FAM_PROG_GUIDE_1.pdf

    The 8051 Bible Chapter 3: Hardware description
    http://www.nxp.com/acrobat_download/various/80C51_FAM_HARDWARE_1.pdf

    Also see:
    http://www.8052.com/faq.phtml
    http://www.8052.com/tutorial.phtml
    http://www.8052.com/
     
    Guy Macon, Jun 7, 2007
    #5
  6. Of course there is. Any microcontroller that can use external memory
    can do that --- just wire the memory chip control lines (chip select,
    r/w, addresses, data, etc.) accordingly. Not to mention that some
    micros actually *are* von-Neumann architectures to begin with.

    What generally can't be done is to make a von-Neumann architecture CPU
    behave like a Harvard one. Turning off a distinction is always easier
    than to magick one into an existing design after the fact.
     
    Hans-Bernhard Bröker, Jun 7, 2007
    #6
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