Results 1 to 7 of 7

Thread: address

  1. #1

    Default address

    Hello all

    I just got a RAM IC that has 16 address lines, and 8 I/O lines. I want to know
    how dose the address work? and is there a way to hook the stamp up to it?

    Thanks
    A. Conti


    [Non-text portions of this message have been removed]
    Last edited by ForumTools; 09-30-2010 at 04:48 AM. Reason: Forum Migration

  2. #2

    Default

    At 18:32 04/18/02, Anthony Conti wrote:
    >Hello all
    >
    >I just got a RAM IC that has 16 address lines, and 8 I/O lines. I want to
    >know how dose the address work? and is there a way to hook the stamp up to it?

    You need to be a bit more specific about the chip you have because there
    are surely more signals to/from this thing than address and data
    lines. What's the part number? Which Stamp do you have?

    The answer, short, simple, and maybe missing something, is that you don't
    have enough I/O on your Stamp to drive this thing directly to it's full
    capability, but if you feed the address serially to a pair of 74HC595 chips
    you can output a 16-bit address using I think 2 Stamp pins. If you can't
    spare 8 pins for the data, you can play similar games with other chips, but
    you need one chip for input and one for output, again at a cost of only 2
    pins. Then you need a pin to select the chip and one to tell it whether
    you're reading or writing.

    That's the general idea. I'm sure others can fill in more details if
    you'll name the chip specifically.


    Jim H
    Last edited by ForumTools; 09-30-2010 at 04:48 AM. Reason: Forum Migration

  3. #3

    Default

    >You need to be a bit more >specific about the chip you have >because there
    >are surely more signals to/from >this thing than address and data
    >lines. What's the part number? >Which Stamp do you have?

    The Chip is A "NEC" P/N D431000ACZ

    http://www.ic.nec.co.jp/memory/pdfs/M11657EJBV0DS00.pdf

    This chip is large in size (memory), and I got it free so I would like to try to
    use it. I am using A BS2p

    Thanks
    A. Conti



    [Non-text portions of this message have been removed]
    Last edited by ForumTools; 09-30-2010 at 04:48 AM. Reason: Forum Migration

  4. #4

    Default

    At 23:53 04/18/02, Anthony Conti wrote:

    > >You need to be a bit more >specific about the chip you have >because there
    > >are surely more signals to/from >this thing than address and data
    > >lines. What's the part number? >Which Stamp do you have?
    >
    >The Chip is A "NEC" P/N D431000ACZ
    >
    >http://www.ic.nec.co.jp/memory/pdfs/M11657EJBV0DS00.pdf
    >
    >This chip is large in size (memory), and I got it free so I would like to
    >try to use it. I am using A BS2p
    >
    >Thanks
    >A. Conti

    Anthony,

    A 74HC595 chip can be used as a serial-to-8bit parallel device and two of
    these can be cascaded to provide a 16-bit address all at the expense of
    three stamp pins and use of the Shiftout instruction.

    Same deal for 8 bits of input using the 74LS165. Total of 6 pins used so far.

    A basic circuit using a 74HC595 is in the manual as Note #2 in the BS2
    section on the Shiftin/Shiftout instructions. I'm sure someone on this
    list has a more complete schematic on a website, and probably code to go
    with it.

    Generally speaking, to interface to your RAM, you need to "shiftout" an
    address to your 74HC595 chips, "shiftout" the data if you're writing,
    activate the address and data interface chips to apply the address and data
    to the RAM, then set the Write Enable pin to either read or write, then
    activate a Chip Select pin to activate the RAM, then if you're reading you
    need to "shiftin" the data being read. When you're done, deselect the RAM
    and the interface chips. Repeat as necessary.

    The date sheet for the RAM describes the pinout on page 3 and the
    combination of pins needed for various desired states on page 7. The
    sequence of operations is shown graphically elsewhere, I forget the page.

    If this still sounds interesting, but you need more details, I'm afraid
    someone else who has more hands-on experience with the Stamp will need to
    supply them.

    Jim H
    Last edited by ForumTools; 09-30-2010 at 04:48 AM. Reason: Forum Migration

  5. #5

    Default

    >If this still sounds interesting, but you need more >details, I'm afraid
    >someone else who has more hands-on >experience with the Stamp will need to
    >supply them.

    >Jim H

    Thank you Jim, but I do not understand how address work. Is it that:

    address slot 1, I can store a 8 bit value.
    address slot 2, I can store a 8 bit value.
    address slot 3, I can store a 8 bit value.
    Ect.

    Is this the way address work?

    Thanks
    A. Conti


    [Non-text portions of this message have been removed]
    Last edited by ForumTools; 09-30-2010 at 04:48 AM. Reason: Forum Migration

  6. #6

    Default

    A memory device is organized by address and contents at that address.
    Different organizations are available. Let take fo example a simple one
    that is labelled 16X8. This would mean that there are 16 separate
    addresses whose locations would be listed in binary or 0001 0010 0011
    -- up to 1111. At each of those 16 addresses you would have the
    potential of storing 1 byte, 2 nibbles, or 16 bits. RAM chips usually
    have an I/O bus where as the info of those 8 bits are stored or
    retrieved. They usually have a R/W line which is going to determine at
    a point in the cycle if info is going to be written to the RAM or read
    from the RAM. There is also typically going to be one or more chip
    enable lines, which is just as it sounds they enable the chip. And
    there maybe more lines of control. All the control lines are referred
    to as a control bus. RAM chips that are serial in nature, do the same
    kind of things, but this info for the address, data and control maybe
    all transferred to the chip over a single serial line. I taught this
    stuff for 15+ years and I could probably ramble on for at least another
    hour, but I think I will stop here and see what kind of questions you
    might have. I would recommend doing a google search for digital
    electronics, RAM organization, or just get the data sheet for the chip
    you are interested in. Sometimes, if the moon is right, you will get
    lucky, LIKE ME, and find an apps engineer who knows enough about his
    subject to make it clear to some one who is just learning.

    HTH,

    Leroy

    Anthony Conti wrote:
    >
    > >If this still sounds interesting, but you need more >details, I'm afraid
    > >someone else who has more hands-on >experience with the Stamp will need to
    > >supply them.
    >
    > >Jim H
    >
    > Thank you Jim, but I do not understand how address work. Is it that:
    >
    > address slot 1, I can store a 8 bit value.
    > address slot 2, I can store a 8 bit value.
    > address slot 3, I can store a 8 bit value.
    > Ect.
    >
    > Is this the way address work?
    >
    > Thanks
    > A. Conti
    >
    > [Non-text portions of this message have been removed]
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and Body
    of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    Last edited by ForumTools; 09-30-2010 at 04:48 AM. Reason: Forum Migration

  7. #7

    Default

    At 18:36 04/19/02, Anthony Conti wrote:
    > >If this still sounds interesting, but you need more >details, I'm afraid
    > >someone else who has more hands-on >experience with the Stamp will need to
    > >supply them.
    >
    > >Jim H
    >
    >Thank you Jim, but I do not understand how address work. Is it that:
    >
    >address slot 1, I can store a 8 bit value.
    >address slot 2, I can store a 8 bit value.
    >address slot 3, I can store a 8 bit value.
    >Ect.
    >
    >Is this the way address work?

    Yes, exactly. And the 17 address lines on your RAM chip (A0 - A16)
    represent 131,072 addresses, or in computer math 128K.

    I just noticed I wasn't paying close enough attention earlier so I didn't
    notice you had 17 address lines instead of 16. So two 8-bit
    serial-to-parallel chips won't address all of your RAM; you'll need three -
    or else dedicate one more Stamp pin to the task. Two chips will address
    64K, half your RAM. If you go ahead, you might consider putting the 17th
    line on a separate Stamp pin (or a dip switch) and have two banks of 64K,
    either switched by software or manually. Or if 64K is enough, just tie the
    17th address line (A16) low - to ground.

    Jim H
    Last edited by ForumTools; 09-30-2010 at 04:48 AM. Reason: Forum Migration

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts