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8051 64k RAM

Discussion in 'Embedded' started by Manikandan, Nov 28, 2003.

  1. Manikandan

    Manikandan Guest

    Hi ,
    I am developing on POS system. I need maximum memory supported by
    8051 i.e 64k. I am an newbie to 8051. Can anybody suggest the RAM
    chips, manufacturers. Also plz suggest how to connect 64k RAM and 64k

    Thanks in advance.

    Manikandan, Nov 28, 2003
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  2. Manikandan

    Rinux Guest


    flat 16 mb address space.
    You can use any flash-ram you need

    Rinux, Nov 28, 2003
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  3. Manikandan

    Tilmann Reh Guest

    And you think this is the right approach for a newbie who
    doesn't even know how to attach memory to the 8051?

    I would rather suggest to simply read the data sheets and user
    manuals of the standard 80C51 which are available from different
    For a start, I would suggest looking at Atmel and Philips for their
    89C51/52 parts. They also offer a lot of application notes.

    (And to the OP: read before asking.)

    Dipl.-Ing. Tilmann Reh
    Autometer GmbH Siegen - Elektronik nach Maß.

    In a world without walls and fences, who needs Windows and Gates ?
    (Sun Microsystems)
    Tilmann Reh, Nov 28, 2003
  4. Manikandan

    MArk Guest

    You should look unde external RAM connecting, and for EEPROM you can use
    serial EEPROM with I2C protocol.

    But why do you need soo much RAM couldn't 1024 bytes be enough?
    BTW, T89C51CC01 , T89C51AC2 and similar chips from Atmel (Temic & Wireless)
    have 1kB of RAM and 1kB of EEPROM on-chip.
    MArk, Nov 28, 2003
  5. Manikandan

    Paul Burke Guest

    The 89C51RD2 (which is really an 8xC52) has 64k flash built in, so you
    can use that. Rumour has it that the Philips version has fewer problems
    than the Atmel.

    You'll need external RAM, just a 74HC573 to latch the address bits.
    You'll lose nearly all the IO lines though (3 ports worth), so you might
    need a bit of address decoding (74HC/AC138) and external IO (just 74HC's
    again) to make up, and you'll end up with a bit less than 64k RAM.
    Almost any 5V 1Mx8 SRAM will give you far more than you can cope with.

    Paul Burke
    Paul Burke, Nov 28, 2003
  6. Manikandan

    Alex Gibson Guest

    May I suggest having a read of all the tutorials www.8052.com

    Also the datasheets and app notes from the 8051 chip manufacturer.



    Alex Gibson, Nov 28, 2003
  7. Manikandan

    Chris Hills Guest

    see the C51 Primer at
    there are basic circuit diagrams in that.
    There are plenty of flash based 8051 types with 64K of on chip flash
    Atmel and Philips do some. These will not need any additional memory

    \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/\
    /\/\/ www.phaedsys.org \/\/
    Chris Hills, Nov 28, 2003
  8. Manikandan

    Chris Hills Guest

    I assume you sell Philips?
    ? why?

    \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/\
    /\/\/ www.phaedsys.org \/\/
    Chris Hills, Nov 28, 2003
  9. Manikandan

    Chris Hills Guest

    You will also need a compiler to support the 24 bit addressing.

    The most expensive of the Keil compiler suites does... but why would you
    need this much memory? All the 8051 compilers from the free ones to the
    most expensive will support the 64K model.

    \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/\
    /\/\/ www.phaedsys.org \/\/
    Chris Hills, Nov 28, 2003
  10. Manikandan

    Chris Hills Guest

    I would not suggest an I2C EEPROM... keep it simple just use ordinary
    why the CC01 or AC2? It is highly unlikey that the O/P will need CAN on
    a POS!! The Rd2 (Atmel or Philips) or preferably the Atmel EM2 as the
    RD2 is being phased out.

    \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/\
    /\/\/ www.phaedsys.org \/\/
    Chris Hills, Nov 28, 2003
  11. "Manikandan"
    Go to http://www.st.com/micropsd/
    and study the uPSD32 and uPSD33 families.
    Will likely do all you need in a single device.

    Also study the AT89C51ED2 and AT89C51ID2 devices.
    Then, work out how much memory your app will actually need,
    including access tolerance, and NV needs -
    you can save chip count, for example, by using FRAM
    to blur the RAM/EE boundary - so AT89C51ID2 and FRAM
    would be a two chip option.
    Jim Granville, Nov 28, 2003
  12. Manikandan

    Alex Gibson Guest

    another chip would be the winbond
    with 64KB flash

    or with 128KB flash

    also have you looked at any of the cygnal 8051 chips ?

    but easy way to find app notes etc is google

    intel app notes

    Philips app notes

    interfacing 8051 with 2 wire chips

    dallas maxim 8051 app notes

    Alex Gibson, Nov 29, 2003
  13. Manikandan

    Neil Bradley Guest

    From my personal experience with the T89C51RD2, AT89C51RD2, and the
    P89C51RD2, this is certainly false. I'd recommend the AT89C51RD2 (not the
    T89C51RD2 since it has reset/low voltage/brownout flash corruption
    problems). It has worked flawlessly in the last 2 products I've worked on. I
    can't say the same about the Philips, though. Besides being less flexible
    (bytewise programming in the flash not available), I couldn't get Philips to
    actually ship any to me.

    Neil Bradley, Nov 29, 2003
  14. Manikandan

    Paul Burke Guest

    No, just used it in a few jobs.
    Because the OP said he wanted 64k, and there's only 1k on chip.

    Paul Burke
    Paul Burke, Dec 1, 2003
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