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Re: Memory Map of elf

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  • wa9hsl
    I also built a one-size-fits-all Elf a few years ago. The VIP rom, the Netronics 256-byte monitor and EHOPS were all put in a single 2716 eprom at location
    Message 1 of 29 , Dec 10, 2003
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      I also built a "one-size-fits-all" Elf a few years ago. The VIP rom,
      the Netronics 256-byte monitor and EHOPS were all put in a single
      2716 eprom at location x'8000' and I think that there was a good bit
      of space left. The system itself was a bit of a monster and with leds
      on all the address lines, a time-of-day clock and a variable speed
      CPU clock.

      At first out of laziness I had restart logic in place that made the
      eprom appear at location x'0000' and then by sensing the next branch
      instruction it "closed the trapdoor" and re-addressed itself at
      x'8000'. All this just to save loading the 3-byte long branch
      instruction.

      Then I decided that there were times that I wanted to actually begin
      programs at location x'0000' from reset to maintain better
      compatibility with simpler Elf software. So I removed the wire-wrap
      logic.

      After doing all that I've since decided that one can get too much
      crammed into a nice little system like the Elf where the main
      attraction is simplicity and understanding of how the everything
      works. The "one-size-fits-all" Elf still runs but I don't use it
      much. I now have several simpler Elf systems each with a limited set
      of compatibility features. They are more fun!

      By the way, you might want to look at the Netronics monitor since it
      has good cassette tape routines also coded into the 256 powerful
      little bytes!

      :o)

      al winfrey - wa9hsl
      ....



      --- In cosmacelf@yahoogroups.com, "Allen Bong" <sfbong@t...> wrote:
      > Hi group,
      >
      > Was it a bit unconventional to start a 1802 with ram at address
      0000? Wouldn't it be better if ROM was placed at 0000? In this
      > way any monitor program would be able to start execution after the
      cpu is reset.
      >
      > I am putting the EHOPS program in an 2716 eprom at 0800. Every
      time I want to use the program I have to put 30 08 00 at
      > address 0000 using the toggle switches. Is there any way I can add
      in some decoding logic controlled by a switch so I can swap
      > the address of the rom at 0800 with the ram at 0000 so I can have
      the option of using the keypad entry or toggle switch entry if I
      > wish.......
      >
      > Thanks.
      >
      > Allen
    • Richard
      see below ... From: Allen Bong To: Sent: Wednesday, December 10, 2003 1:04 AM Subject: [cosmacelf] Re: Memory
      Message 2 of 29 , Dec 10, 2003
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        see below


        ----- Original Message -----
        From: "Allen Bong" <sfbong@...>
        To: <cosmacelf@yahoogroups.com>
        Sent: Wednesday, December 10, 2003 1:04 AM
        Subject: [cosmacelf] Re: Memory Map of elf


        > --- In cosmacelf@yahoogroups.com, "Richard" <stateamuse@c...> wrote:
        > > If The EHOPS program does not care where it is, and fine's it on
        > memory.
        > > You could put a double pole double throw switch in. Connected to
        > the chip
        > > select lines of the ram and Rom to switch these two around. Assum
        > following
        > > pin out of switch
        > > 1 2
        > > 3 4
        > > 5 6
        > > connect pin 1 to 6, 2 to 5, input ram to 3, input rom to 4,
        > output to
        > > ram 2 or 5, output to rom 1 or 6
        > >
        > > flipping switch would just reverse these to lines. You will need
        > make sure
        > > the connection you make leaves a pull up resistor connected to the
        > ram and
        > > rom, and that you put it in a place that they are both the same
        > polarity,
        > > 2716's chip select is active LOW. I don't Know what your ram's are.
        > >
        >
        > My ram are the similar one as used in the elf but it was of cmos
        > favour: - 5101
        >
        > > One note I Beleive you would have to be entering C0 08 00 not 30
        > 08. 30 08
        > > 00 would branch to address 0008.
        >
        >
        > Sorry, I forgot that there is a long branch for it.
        >
        >
        > >
        > > To Answer the other question about It Being Conventional.
        > >
        > > For Dedicatied Use It Is common to start it with rom at 0000. But
        > not for
        > > none dedicated use, most other programs start at 0000, with a rom
        > in the way
        > > they would not work. The soultion most used to solve this is zero
        > power
        > > rams or battery backup.
        > >
        > > I am sure there are other ways to switch this. But I would Have to
        > See how
        > > you decoded the 2716 and the Ram.
        >
        >
        > > I used almost the same scheme as described in Part 3 of the PE
        > construction
        > articles. Instead of using a 4 bit latch 4042 which I dont have any
        > in my
        > junk box, I used a 74HC174 6 bit latch together with a 74HC04 to get
        > the
        > inverted address /A10 for addressing the onboard 256 byte RAM. Out

        This is a problem the input of the 74HC04 needs to be moved to the /Y0
        output.
        of the decoder. (when the ROM is Address, A10 is still low so both the rom
        and ram is on.)

        The switch above would still be the way i would go, to keep it simple. when
        you get up to running the Tiny monitor combo, some one already has it set up
        to run from rom at 8000, and you will wont to reconfigure the way you are
        addressing. One word Of note: after you enter C0 08 00 a dozen or so times,
        you will get to a point you can do it in about 30 sec. adding the battery
        part of the artical would be a better use of your time. Then you put it in
        once and it will stay.

        if you use the switch, Then Put a 10k resistor from the input of the 74HC04
        to +5V, cut the line between the resistor and the decoder(if it is connected
        yet).

        Then put a 10k resistor from CE of the 2716 to +5V, and cut the line between
        the resistor and the decoder.

        you would than be reversing the /Y0 and /Y1 lines, the reason for the
        resistors it that when the switch is flipped, there is a time (ms) that
        nothing would be connected, and this could cause damage. You can then flip
        the switch with power on (processor not running).

        uses the decoder side as input on the switch.

        > of the
        > A8-A13 coming out of the '174, A11-A13 were used as inputs of a
        > 74HC138
        > 1-out-of-8-decoder. /Y0 output was left NC and /Y1 (0800-0FFF) was
        > connected to the /CS of the 2716. The /OE of 2716 was connected
        > to /MRD of
        > 1802. /Y2
        > was connected to the second 2716 and /Y3 to /Y7 were reserved for
        > future
        > use.
        >
        > The circuit was constructed on a 2"X4" perforated board and connected
        > to the
        > elf through a 26 pin ribbon cable. As I have plenty of 2716s
        > (savaged from
        > junked OKI teleprinter machines), there is no problem for me to
        > extend the
        > Eprom board when the program grows larger. I think I'd finally get
        > the Tiny
        > Basic and the IDIOT4 to run on my Elf after I get the serial interface
        > functioning.
        >
        > Regards
        >
        > Allen
        >
        >
        >
        > >
        > > ----- Original Message -----
        > > From: "Allen Bong" <sfbong@t...>
        > > To: <cosmacelf@yahoogroups.com>
        > > Sent: Tuesday, December 09, 2003 8:11 PM
        > > Subject: [cosmacelf] Memory Map of elf
        > >
        > >
        > > > Hi group,
        > > >
        > > > Was it a bit unconventional to start a 1802 with ram at address
        > 0000?
        > > Wouldn't it be better if ROM was placed at 0000? In this
        > > > way any monitor program would be able to start execution after
        > the cpu is
        > > reset.
        > > >
        > > > I am putting the EHOPS program in an 2716 eprom at 0800. Every
        > time I
        > > want to use the program I have to put 30 08 00 at
        > > > address 0000 using the toggle switches. Is there any way I can
        > add in
        > > some decoding logic controlled by a switch so I can swap
        > > > the address of the rom at 0800 with the ram at 0000 so I can have
        > the
        > > option of using the keypad entry or toggle switch entry if I
        > > > wish.......
        > > >
        > > > Thanks.
        > > >
        > > > Allen
        > > >
        > > >
        > > >
        > > >
        > > >
        > > >
        > > > ========================================================
        > > > Visit the COSMAC ELF website at http://www.cosmacelf.com, or view
        > the
        > > Wiki/FAQ at http://1802.bitting.com/
        > > >
        > > > To unsubscribe from this group, send an email to:
        > > > cosmacelf-unsubscribe@yahoogroups.com
        > > >
        > > >
        > > >
        > > > Your use of Yahoo! Groups is subject to
        > http://docs.yahoo.com/info/terms/
        > > >
        > > >
        >
        >
        >
        > ========================================================
        > Visit the COSMAC ELF website at http://www.cosmacelf.com, or view the
        Wiki/FAQ at http://1802.bitting.com/
        >
        > To unsubscribe from this group, send an email to:
        > cosmacelf-unsubscribe@yahoogroups.com
        >
        >
        >
        > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
        >
        >
      • Allen Bong
        ... wrote: Hi Josh, I have looked through your schematic and I found it very simple and well designed. Am I right understanding its working as below when the
        Message 3 of 29 , Dec 11, 2003
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          --- In cosmacelf@yahoogroups.com, "joshbensadon" <joshbensadon@y...>
          wrote:

          Hi Josh,

          I have looked through your schematic and I found it very simple and
          well designed. Am I right understanding its working as below when
          the vip/elf switch is at the left?

          1. When the elf is switched on and the "RUN" is on, A15 should be at
          low.

          2. After completed executing LBRA 8003, A15 turns high and continue
          to run from 8003 normally as an eprom.

          3. OR A15 will become high after the F8 80 B3, F8 07 A3, D3 (sep r3)
          sequence at 8007.

          4. If the rom routine is accessing the ram as temporary variables,
          it should work.

          Allen


          > Hi Allen,
          >
          > > Yes, Your schematic on how you did it is very much appreciated.
          You
          > > may either email me direct to sfbong(at)tm(dot)net(dot)my or
          post it
          > > to the "files" section so any one who is interested may retrieve
          it.
          > >
          > > The schematics on how the VIP implement the ghosting would be
          nice
          > > too if you have it.
          >
          > It's the same idea, ghosting the EPROM is what VIP did.
          > I will post the file in my folder, members-JoshBensadon.
          >
          > It uses just 2 chips, 74HC00 and 74HC02, available in any junk
          box! :)
          >
          > Regards,
          > Josh
        • Allen Bong
          ... From: Richard To: Sent: Thursday, December 11, 2003 9:12 AM Subject: Re: [cosmacelf] Re: Memory Map of
          Message 4 of 29 , Dec 11, 2003
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            ----- Original Message -----
            From: "Richard" <stateamuse@...>
            To: <cosmacelf@yahoogroups.com>
            Sent: Thursday, December 11, 2003 9:12 AM
            Subject: Re: [cosmacelf] Re: Memory Map of elf


            see below

            [..................text snipped...............】

            > > > I used almost the same scheme as described in Part 3 of the PE
            > > construction
            > > articles. Instead of using a 4 bit latch 4042 which I dont have any
            > > in my
            > > junk box, I used a 74HC174 6 bit latch together with a 74HC04 to get
            > > the
            > > inverted address /A10 for addressing the onboard 256 byte RAM. Out
            >

            > This is a problem the input of the 74HC04 needs to be moved to the /Y0
            > output.
            > of the decoder. (when the ROM is Address, A10 is still low so both the
            rom
            > and ram is on.)

            Oop, I must have over-looked this one. But the EHOPS still works as it is
            less than 256 bytes long.
            I think problems will surface when executing programs starting from
            0c00-0fff when A10 turns high.

            .................................................snipped....................
            ..........
          • Richard
            You must have something else connected, Is Anything connected to the decoder enable lines (pins 4,5,6). If The RAM is Address At 0 then there would be a
            Message 5 of 29 , Dec 11, 2003
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              You must have something else connected, Is Anything connected to the
              decoder enable lines (pins 4,5,6).
              If The RAM is Address At 0 then there would be a problem with with
              addressing 0800. The A10 line is low in both cases.



              ----- Original Message -----
              From: "Allen Bong" <sfbong@...>
              To: <cosmacelf@yahoogroups.com>
              Sent: Thursday, December 11, 2003 9:10 AM
              Subject: Re: [cosmacelf] Re: Memory Map of elf


              >
              > ----- Original Message -----
              > From: "Richard" <stateamuse@...>
              > To: <cosmacelf@yahoogroups.com>
              > Sent: Thursday, December 11, 2003 9:12 AM
              > Subject: Re: [cosmacelf] Re: Memory Map of elf
              >
              >
              > see below
              >
              > [..................text snipped...............】
              >
              > > > > I used almost the same scheme as described in Part 3 of the PE
              > > > construction
              > > > articles. Instead of using a 4 bit latch 4042 which I dont have any
              > > > in my
              > > > junk box, I used a 74HC174 6 bit latch together with a 74HC04 to get
              > > > the
              > > > inverted address /A10 for addressing the onboard 256 byte RAM. Out
              > >
              >
              > > This is a problem the input of the 74HC04 needs to be moved to the /Y0
              > > output.
              > > of the decoder. (when the ROM is Address, A10 is still low so both the
              > rom
              > > and ram is on.)
              >
              > Oop, I must have over-looked this one. But the EHOPS still works as it is
              > less than 256 bytes long.
              > I think problems will surface when executing programs starting from
              > 0c00-0fff when A10 turns high.
              >
              >
              .................................................snipped....................
              > ..........
              >
              >
              >
              >
              > ========================================================
              > Visit the COSMAC ELF website at http://www.cosmacelf.com, or view the
              Wiki/FAQ at http://1802.bitting.com/
              >
              > To unsubscribe from this group, send an email to:
              > cosmacelf-unsubscribe@yahoogroups.com
              >
              >
              >
              > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
              >
              >
            • Allen Bong
              ... No, pins 4&5 are gounded and pin 6 was connected to Vcc. The ram was enabled using the /A10 using HC04. So when my program executes from 0800 to 08FF,
              Message 6 of 29 , Dec 11, 2003
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                --- In cosmacelf@yahoogroups.com, "Richard" <stateamuse@c...> wrote:

                No, pins 4&5 are gounded and pin 6 was connected to Vcc. The ram was
                enabled using the /A10 using HC04. So when my program executes from
                0800 to 08FF, /A10 was high all the time: ie. (0000,1000,0000,0000 to
                0000,1000,1111,1111).

                Allen



                > You must have something else connected, Is Anything connected to
                the
                > decoder enable lines (pins 4,5,6).
                > If The RAM is Address At 0 then there would be a problem with with
                > addressing 0800. The A10 line is low in both cases.
                >
                >
                >
                > ----- Original Message -----
                > From: "Allen Bong" <sfbong@t...>
                > To: <cosmacelf@yahoogroups.com>
                > Sent: Thursday, December 11, 2003 9:10 AM
                > Subject: Re: [cosmacelf] Re: Memory Map of elf
                >
                >
                > >
                > > ----- Original Message -----
                > > From: "Richard" <stateamuse@c...>
                > > To: <cosmacelf@yahoogroups.com>
                > > Sent: Thursday, December 11, 2003 9:12 AM
                > > Subject: Re: [cosmacelf] Re: Memory Map of elf
                > >
                > >
                > > see below
                > >
                > > [..................text snipped...............ã€`
                > >
                > > > > > I used almost the same scheme as described in Part 3 of the
                PE
                > > > > construction
                > > > > articles. Instead of using a 4 bit latch 4042 which I dont
                have any
                > > > > in my
                > > > > junk box, I used a 74HC174 6 bit latch together with a 74HC04
                to get
                > > > > the
                > > > > inverted address /A10 for addressing the onboard 256 byte
                RAM. Out
                > > >
                > >
                > > > This is a problem the input of the 74HC04 needs to be moved to
                the /Y0
                > > > output.
                > > > of the decoder. (when the ROM is Address, A10 is still low so
                both the
                > > rom
                > > > and ram is on.)
                > >
                > > Oop, I must have over-looked this one. But the EHOPS still works
                as it is
                > > less than 256 bytes long.
                > > I think problems will surface when executing programs starting
                from
                > > 0c00-0fff when A10 turns high.
                > >
                > >
                > .................................................snipped............
                ........
                > > ..........
                > >
                > >
                > >
                > >
                > > ========================================================
                > > Visit the COSMAC ELF website at http://www.cosmacelf.com, or view
                the
                > Wiki/FAQ at http://1802.bitting.com/
                > >
                > > To unsubscribe from this group, send an email to:
                > > cosmacelf-unsubscribe@yahoogroups.com
                > >
                > >
                > >
                > > Your use of Yahoo! Groups is subject to
                http://docs.yahoo.com/info/terms/
                > >
                > >
              • sfbong@tm.net.my
                Hi Richard, I myself was also quite confused how the ram works when the 2716 was enabled. Anyway the card is still with me and I am going to trace the
                Message 7 of 29 , Dec 11, 2003
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                  Hi Richard,

                  I myself was also quite confused how the ram works when the 2716 was enabled. Anyway the card is still with me and I am going to trace the schematic again to-night just to solve the mystery. Sorry for any misleading informations that I gave!

                  Allen.


                  ----- Original Message -----
                  From: Allen Bong <sfbong@...>
                  Date: Friday, December 12, 2003 11:11 am
                  Subject: [cosmacelf] Re: Memory Map of elf

                  > --- In cosmacelf@yahoogroups.com, "Richard" <stateamuse@c...> wrote:
                  >
                  > No, pins 4&5 are gounded and pin 6 was connected to Vcc. The ram
                  > was
                  > enabled using the /A10 using HC04. So when my program executes
                  > from
                  > 0800 to 08FF, /A10 was high all the time: ie. (0000,1000,0000,0000
                  > to
                  > 0000,1000,1111,1111).
                  >
                  > Allen
                  >
                  >
                  >
                  > > You must have something else connected, Is Anything connected
                  > to
                  > the
                  > > decoder enable lines (pins 4,5,6).
                  > > If The RAM is Address At 0 then there would be a problem with with
                  > > addressing 0800. The A10 line is low in both cases.
                  > >
                  > >
                  > >
                  > > ----- Original Message -----
                  > > From: "Allen Bong" <sfbong@t...>
                  > > To: <cosmacelf@yahoogroups.com>
                  > > Sent: Thursday, December 11, 2003 9:10 AM
                  > > Subject: Re: [cosmacelf] Re: Memory Map of elf
                  > >
                  > >
                  > > >
                  > > > ----- Original Message -----
                  > > > From: "Richard" <stateamuse@c...>
                  > > > To: <cosmacelf@yahoogroups.com>
                  > > > Sent: Thursday, December 11, 2003 9:12 AM
                  > > > Subject: Re: [cosmacelf] Re: Memory Map of elf
                  > > >
                  > > >
                  > > > see below
                  > > >
                  > > > [..................text snipped...............ã?`
                  > > >
                  > > > > > > I used almost the same scheme as described in Part 3 of
                  > the
                  > PE
                  > > > > > construction
                  > > > > > articles. Instead of using a 4 bit latch 4042 which I
                  > dont
                  > have any
                  > > > > > in my
                  > > > > > junk box, I used a 74HC174 6 bit latch together with a
                  > 74HC04
                  > to get
                  > > > > > the
                  > > > > > inverted address /A10 for addressing the onboard 256 byte
                  > RAM. Out
                  > > > >
                  > > >
                  > > > > This is a problem the input of the 74HC04 needs to be moved
                  > to
                  > the /Y0
                  > > > > output.
                  > > > > of the decoder. (when the ROM is Address, A10 is still low
                  > so
                  > both the
                  > > > rom
                  > > > > and ram is on.)
                  > > >
                  > > > Oop, I must have over-looked this one. But the EHOPS still
                  > works
                  > as it is
                  > > > less than 256 bytes long.
                  > > > I think problems will surface when executing programs starting
                  > from
                  > > > 0c00-0fff when A10 turns high.
                  > > >
                  > > >
                  > > .................................................snipped............
                  > ........
                  > > > ..........
                  > > >
                  > > >
                  > > >
                  > > >
                  > > > ========================================================
                  > > > Visit the COSMAC ELF website at http://www.cosmacelf.com, or
                  > view
                  > the
                  > > Wiki/FAQ at http://1802.bitting.com/
                  > > >
                  > > > To unsubscribe from this group, send an email to:
                  > > > cosmacelf-unsubscribe@yahoogroups.com
                  > > >
                  > > >
                  > > >
                  > > > Your use of Yahoo! Groups is subject to
                  > http://docs.yahoo.com/info/terms/
                  > > >
                  > > >
                  >
                  >
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                • Richard
                  see below ... From: Allen Bong To: Sent: Thursday, December 11, 2003 10:11 PM Subject: [cosmacelf] Re: Memory
                  Message 8 of 29 , Dec 11, 2003
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                    see below

                    ----- Original Message -----
                    From: "Allen Bong" <sfbong@...>
                    To: <cosmacelf@yahoogroups.com>
                    Sent: Thursday, December 11, 2003 10:11 PM
                    Subject: [cosmacelf] Re: Memory Map of elf


                    --- In cosmacelf@yahoogroups.com, "Richard" <stateamuse@c...> wrote:

                    No, pins 4&5 are gounded and pin 6 was connected to Vcc. The ram was
                    enabled using the /A10 using HC04. So when my program executes from
                    0800 to 08FF, /A10 was high all the time: ie. (0000,1000,0000,0000 to
                    0000,1000,1111,1111).

                    Yes This Is True. Note: A10 is LOW and /A10 Would still be High
                    the only reason the inverter was used is because the 5101 RAM is active High
                    instead of Low like the ROM. So anytime You use your ROM The RAM is active.
                    The ROM must be winning when there is a read. The Fact that the Rom is not
                    active when Ram is used is what is making it work, But I Don't Know How Long
                    The Ram chips Can take the punishment.


                    Allen



                    > You must have something else connected, Is Anything connected to
                    the
                    > decoder enable lines (pins 4,5,6).
                    > If The RAM is Address At 0 then there would be a problem with with
                    > addressing 0800. The A10 line is low in both cases.
                    >
                    >
                    >
                    > ----- Original Message -----
                    > From: "Allen Bong" <sfbong@t...>
                    > To: <cosmacelf@yahoogroups.com>
                    > Sent: Thursday, December 11, 2003 9:10 AM
                    > Subject: Re: [cosmacelf] Re: Memory Map of elf
                    >
                    >
                    > >
                    > > ----- Original Message -----
                    > > From: "Richard" <stateamuse@c...>
                    > > To: <cosmacelf@yahoogroups.com>
                    > > Sent: Thursday, December 11, 2003 9:12 AM
                    > > Subject: Re: [cosmacelf] Re: Memory Map of elf
                    > >
                    > >
                    > > see below
                    > >
                    > > [..................text snipped...............ã?`
                    > >
                    > > > > > I used almost the same scheme as described in Part 3 of the
                    PE
                    > > > > construction
                    > > > > articles. Instead of using a 4 bit latch 4042 which I dont
                    have any
                    > > > > in my
                    > > > > junk box, I used a 74HC174 6 bit latch together with a 74HC04
                    to get
                    > > > > the
                    > > > > inverted address /A10 for addressing the onboard 256 byte
                    RAM. Out
                    > > >
                    > >
                    > > > This is a problem the input of the 74HC04 needs to be moved to
                    the /Y0
                    > > > output.
                    > > > of the decoder. (when the ROM is Address, A10 is still low so
                    both the
                    > > rom
                    > > > and ram is on.)
                    > >
                    > > Oop, I must have over-looked this one. But the EHOPS still works
                    as it is
                    > > less than 256 bytes long.
                    > > I think problems will surface when executing programs starting
                    from
                    > > 0c00-0fff when A10 turns high.
                    > >
                    > >
                    > .................................................snipped............
                    ........
                    > > ..........
                    > >
                    > >
                    > >
                    > >
                    > > ========================================================
                    > > Visit the COSMAC ELF website at http://www.cosmacelf.com, or view
                    the
                    > Wiki/FAQ at http://1802.bitting.com/
                    > >
                    > > To unsubscribe from this group, send an email to:
                    > > cosmacelf-unsubscribe@yahoogroups.com
                    > >
                    > >
                    > >
                    > > Your use of Yahoo! Groups is subject to
                    http://docs.yahoo.com/info/terms/
                    > >
                    > >



                    ========================================================
                    Visit the COSMAC ELF website at http://www.cosmacelf.com, or view the
                    Wiki/FAQ at http://1802.bitting.com/

                    To unsubscribe from this group, send an email to:
                    cosmacelf-unsubscribe@yahoogroups.com



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                  • joshbensadon
                    Allen, ... Yes, that is right. ... Well, A15 turns high for some reason when the C8 instruction is loaded that is why A15 is AND d with MRead, so the flip/flop
                    Message 9 of 29 , Dec 12, 2003
                    • 0 Attachment
                      Allen,


                      > 1. When the elf is switched on and the "RUN" is on, A15 should be at
                      > low.

                      Yes, that is right.

                      > 2. After completed executing LBRA 8003, A15 turns high and continue
                      > to run from 8003 normally as an eprom.
                      > 3. OR A15 will become high after the F8 80 B3, F8 07 A3, D3 (sep r3)
                      > sequence at 8007.

                      Well, A15 turns high for some reason when the C8 instruction is loaded
                      that is why A15 is AND'd with MRead, so the flip/flop only sets once
                      an actual Memory Read where A15 is high. This will occur when the
                      1802 does the next instruction fetch after the LBRA 8003 or the SEP R3.
                      Once it does this, the EPROM ghosting is over and the RAM is accessible
                      @ addresses 0000-7FFF.

                      > 4. If the rom routine is accessing the ram as temporary variables,
                      > it should work.

                      Yes.

                      Josh
                    • Allen Bong
                      ... Richard, I must apologize for the wrong informations given on my earlier posts. After tracing the circuit board, I found that the inverter was actually
                      Message 10 of 29 , Dec 12, 2003
                      • 0 Attachment
                        --- In cosmacelf@yahoogroups.com, "Richard" <stateamuse@c...> wrote:
                        > see below
                        >
                        > ----- Original Message -----
                        > From: "Allen Bong" <sfbong@t...>
                        > To: <cosmacelf@yahoogroups.com>
                        > Sent: Thursday, December 11, 2003 10:11 PM
                        > Subject: [cosmacelf] Re: Memory Map of elf
                        >
                        >
                        > --- In cosmacelf@yahoogroups.com, "Richard" <stateamuse@c...> wrote:
                        >

                        Richard,

                        I must apologize for the wrong informations given on my earlier posts.

                        After tracing the circuit board, I found that the inverter was
                        actually inverting the TPA signal for the HC174 clock. The strobe of
                        the 4042 was programmable but the HC174 only accepts a low to high in
                        order to latch in A8-A15 on Q output (if that is what I understand
                        from the datasheet).

                        The RAM was chip selected using the A11 signal (not inverted) on pin
                        19 of the 5101. So it is still wrong if a second 2716 is added. I
                        have corrected the mistakes on my EPROM board and I am going to put
                        in Josh's circuit tonight. I just have to change the HC04 to HC00
                        and add another HC02. There was one extra gate on the HC00 which can
                        be used as an inverter for the HC174.

                        There are 2 extra pins on my 26 pin IDC connector for bringing in
                        the "RUN" signal. So I just have to add a change-over toggle switch
                        on the eprom card and reassemble the EHOPS program with the extra
                        instruction at 0800 and I think it should work.

                        I would probably need some help from our group on how to put in a
                        6116 ram with battery backup (or the Dallas RAM) to take over the
                        5101 when I am ready.

                        Allen

                        > No, pins 4&5 are gounded and pin 6 was connected to Vcc. The ram
                        was
                        > enabled using the /A10 using HC04. So when my program executes from
                        > 0800 to 08FF, /A10 was high all the time: ie. (0000,1000,0000,0000
                        to
                        > 0000,1000,1111,1111).
                        >
                        > Yes This Is True. Note: A10 is LOW and /A10 Would still be High
                        > the only reason the inverter was used is because the 5101 RAM is
                        active High
                        > instead of Low like the ROM. So anytime You use your ROM The RAM
                        is active.
                        > The ROM must be winning when there is a read. The Fact that the
                        Rom is not
                        > active when Ram is used is what is making it work, But I Don't Know
                        How Long
                        > The Ram chips Can take the punishment.
                        >
                        >
                        > Allen
                        >
                        >
                        >
                        > > You must have something else connected, Is Anything connected to
                        > the
                        > > decoder enable lines (pins 4,5,6).
                        > > If The RAM is Address At 0 then there would be a problem with with
                        > > addressing 0800. The A10 line is low in both cases.
                        > >
                        > >
                        > >
                        > > ----- Original Message -----
                        > > From: "Allen Bong" <sfbong@t...>
                        > > To: <cosmacelf@yahoogroups.com>
                        > > Sent: Thursday, December 11, 2003 9:10 AM
                        > > Subject: Re: [cosmacelf] Re: Memory Map of elf
                        > >
                        > >
                        > > >
                        > > > ----- Original Message -----
                        > > > From: "Richard" <stateamuse@c...>
                        > > > To: <cosmacelf@yahoogroups.com>
                        > > > Sent: Thursday, December 11, 2003 9:12 AM
                        > > > Subject: Re: [cosmacelf] Re: Memory Map of elf
                        > > >
                        > > >
                        > > > see below
                        > > >
                        > > > [..................text snipped...............ã?`
                        > > >
                        > > > > > > I used almost the same scheme as described in Part 3 of
                        the
                        > PE
                        > > > > > construction
                        > > > > > articles. Instead of using a 4 bit latch 4042 which I dont
                        > have any
                        > > > > > in my
                        > > > > > junk box, I used a 74HC174 6 bit latch together with a
                        74HC04
                        > to get
                        > > > > > the
                        > > > > > inverted address /A10 for addressing the onboard 256 byte
                        > RAM. Out
                        > > > >
                        > > >
                        > > > > This is a problem the input of the 74HC04 needs to be moved to
                        > the /Y0
                        > > > > output.
                        > > > > of the decoder. (when the ROM is Address, A10 is still low so
                        > both the
                        > > > rom
                        > > > > and ram is on.)
                        > > >
                        > > > Oop, I must have over-looked this one. But the EHOPS still
                        works
                        > as it is
                        > > > less than 256 bytes long.
                        > > > I think problems will surface when executing programs starting
                        > from
                        > > > 0c00-0fff when A10 turns high.
                        > > >
                        > > >
                        >
                        > .................................................snipped............
                        > ........
                        > > > ..........
                        > > >
                        > > >
                        > > >
                        > > >
                        > > > ========================================================
                        > > > Visit the COSMAC ELF website at http://www.cosmacelf.com, or
                        view
                        > the
                        > > Wiki/FAQ at http://1802.bitting.com/
                        > > >
                        > > > To unsubscribe from this group, send an email to:
                        > > > cosmacelf-unsubscribe@yahoogroups.com
                        > > >
                        > > >
                        > > >
                        > > > Your use of Yahoo! Groups is subject to
                        > http://docs.yahoo.com/info/terms/
                        > > >
                        > > >
                        >
                        >
                        >
                        > ========================================================
                        > Visit the COSMAC ELF website at http://www.cosmacelf.com, or view
                        the
                        > Wiki/FAQ at http://1802.bitting.com/
                        >
                        > To unsubscribe from this group, send an email to:
                        > cosmacelf-unsubscribe@yahoogroups.com
                        >
                        >
                        >
                        > Your use of Yahoo! Groups is subject to
                        http://docs.yahoo.com/info/terms/
                      • Richard
                        what I was saying about the dallas chip was you could put this in your eprom board, and only change the one pin. and use /Y0 select signal. As for the 6116
                        Message 11 of 29 , Dec 12, 2003
                        • 0 Attachment
                          what I was saying about the dallas chip was you could put this in your eprom
                          board, and only change the one pin. and use /Y0 select signal. As for the
                          6116 battery you need 2- diodes and a 3.6 volt Litium battery. or 1-diode
                          a 270ohm resistor and a 3.6V rechargeable nickel cadium battery, But the
                          Litium will works better. They don't break down and leak all over your
                          circuit board.


                          ----- Original Message -----
                          From: "Allen Bong" <sfbong@...>
                          To: <cosmacelf@yahoogroups.com>
                          Sent: Friday, December 12, 2003 8:29 PM
                          Subject: [cosmacelf] Re: Memory Map of elf


                          --- In cosmacelf@yahoogroups.com, "Richard" <stateamuse@c...> wrote:
                          > see below
                          >
                          > ----- Original Message -----
                          > From: "Allen Bong" <sfbong@t...>
                          > To: <cosmacelf@yahoogroups.com>
                          > Sent: Thursday, December 11, 2003 10:11 PM
                          > Subject: [cosmacelf] Re: Memory Map of elf
                          >
                          >
                          > --- In cosmacelf@yahoogroups.com, "Richard" <stateamuse@c...> wrote:
                          >

                          Richard,

                          I must apologize for the wrong informations given on my earlier posts.

                          After tracing the circuit board, I found that the inverter was
                          actually inverting the TPA signal for the HC174 clock. The strobe of
                          the 4042 was programmable but the HC174 only accepts a low to high in
                          order to latch in A8-A15 on Q output (if that is what I understand
                          from the datasheet).

                          The RAM was chip selected using the A11 signal (not inverted) on pin
                          19 of the 5101. So it is still wrong if a second 2716 is added. I
                          have corrected the mistakes on my EPROM board and I am going to put
                          in Josh's circuit tonight. I just have to change the HC04 to HC00
                          and add another HC02. There was one extra gate on the HC00 which can
                          be used as an inverter for the HC174.

                          There are 2 extra pins on my 26 pin IDC connector for bringing in
                          the "RUN" signal. So I just have to add a change-over toggle switch
                          on the eprom card and reassemble the EHOPS program with the extra
                          instruction at 0800 and I think it should work.

                          I would probably need some help from our group on how to put in a
                          6116 ram with battery backup (or the Dallas RAM) to take over the
                          5101 when I am ready.

                          Allen

                          > No, pins 4&5 are gounded and pin 6 was connected to Vcc. The ram
                          was
                          > enabled using the /A10 using HC04. So when my program executes from
                          > 0800 to 08FF, /A10 was high all the time: ie. (0000,1000,0000,0000
                          to
                          > 0000,1000,1111,1111).
                          >
                          > Yes This Is True. Note: A10 is LOW and /A10 Would still be High
                          > the only reason the inverter was used is because the 5101 RAM is
                          active High
                          > instead of Low like the ROM. So anytime You use your ROM The RAM
                          is active.
                          > The ROM must be winning when there is a read. The Fact that the
                          Rom is not
                          > active when Ram is used is what is making it work, But I Don't Know
                          How Long
                          > The Ram chips Can take the punishment.
                          >
                          >
                          > Allen
                          >
                          >
                          >
                          > > You must have something else connected, Is Anything connected to
                          > the
                          > > decoder enable lines (pins 4,5,6).
                          > > If The RAM is Address At 0 then there would be a problem with with
                          > > addressing 0800. The A10 line is low in both cases.
                          > >
                          > >
                          > >
                          > > ----- Original Message -----
                          > > From: "Allen Bong" <sfbong@t...>
                          > > To: <cosmacelf@yahoogroups.com>
                          > > Sent: Thursday, December 11, 2003 9:10 AM
                          > > Subject: Re: [cosmacelf] Re: Memory Map of elf
                          > >
                          > >
                          > > >
                          > > > ----- Original Message -----
                          > > > From: "Richard" <stateamuse@c...>
                          > > > To: <cosmacelf@yahoogroups.com>
                          > > > Sent: Thursday, December 11, 2003 9:12 AM
                          > > > Subject: Re: [cosmacelf] Re: Memory Map of elf
                          > > >
                          > > >
                          > > > see below
                          > > >
                          > > > [..................text snipped...............ã?`
                          > > >
                          > > > > > > I used almost the same scheme as described in Part 3 of
                          the
                          > PE
                          > > > > > construction
                          > > > > > articles. Instead of using a 4 bit latch 4042 which I dont
                          > have any
                          > > > > > in my
                          > > > > > junk box, I used a 74HC174 6 bit latch together with a
                          74HC04
                          > to get
                          > > > > > the
                          > > > > > inverted address /A10 for addressing the onboard 256 byte
                          > RAM. Out
                          > > > >
                          > > >
                          > > > > This is a problem the input of the 74HC04 needs to be moved to
                          > the /Y0
                          > > > > output.
                          > > > > of the decoder. (when the ROM is Address, A10 is still low so
                          > both the
                          > > > rom
                          > > > > and ram is on.)
                          > > >
                          > > > Oop, I must have over-looked this one. But the EHOPS still
                          works
                          > as it is
                          > > > less than 256 bytes long.
                          > > > I think problems will surface when executing programs starting
                          > from
                          > > > 0c00-0fff when A10 turns high.
                          > > >
                          > > >
                          >
                          > .................................................snipped............
                          > ........
                          > > > ..........
                          > > >
                          > > >
                          > > >
                          > > >
                          > > > ========================================================
                          > > > Visit the COSMAC ELF website at http://www.cosmacelf.com, or
                          view
                          > the
                          > > Wiki/FAQ at http://1802.bitting.com/
                          > > >
                          > > > To unsubscribe from this group, send an email to:
                          > > > cosmacelf-unsubscribe@yahoogroups.com
                          > > >
                          > > >
                          > > >
                          > > > Your use of Yahoo! Groups is subject to
                          > http://docs.yahoo.com/info/terms/
                          > > >
                          > > >
                          >
                          >
                          >
                          > ========================================================
                          > Visit the COSMAC ELF website at http://www.cosmacelf.com, or view
                          the
                          > Wiki/FAQ at http://1802.bitting.com/
                          >
                          > To unsubscribe from this group, send an email to:
                          > cosmacelf-unsubscribe@yahoogroups.com
                          >
                          >
                          >
                          > Your use of Yahoo! Groups is subject to
                          http://docs.yahoo.com/info/terms/



                          ========================================================
                          Visit the COSMAC ELF website at http://www.cosmacelf.com, or view the
                          Wiki/FAQ at http://1802.bitting.com/

                          To unsubscribe from this group, send an email to:
                          cosmacelf-unsubscribe@yahoogroups.com



                          Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
                        • Allen Bong
                          ... 0000? ... the cpu ... machine ... The ... a ... approach. ... CPU ... Hi Dave, I have printed and studied the 3 schematics of the ACE CPU on your cosmac
                          Message 12 of 29 , Dec 13, 2003
                          • 0 Attachment
                            --- In cosmacelf@yahoogroups.com, Dave Ruske <dave@r...> wrote:
                            > On Tuesday, December 9, 2003, at 07:11 PM, Allen Bong wrote:
                            > > Was it a bit unconventional to start a 1802 with ram at address
                            0000?
                            > > Wouldn't it be better if ROM was placed at 0000? In this
                            > > way any monitor program would be able to start execution after
                            the cpu
                            > > is reset.
                            >
                            > The ACE CPU card took the approach of hijacking the first 24
                            machine
                            > cycles, forcing a C0 xx 00 onto the bus to simulate a long branch.
                            The
                            > "xx" was set via DIP switches on the card, allowing it to jump to
                            a
                            > monitor ROM on reset. I thought it was kind of an interesting
                            approach.
                            >
                            > I've been doing some scans recently, I'll try to get to the ACE
                            CPU
                            > card soon.
                            >
                            > Dave

                            Hi Dave,

                            I have printed and studied the 3 schematics of the ACE CPU on your
                            cosmac elf website. I can understand how the instruction C0 pp 00
                            was generated using the 4556. But I cant understand how the RAM
                            (6116 I guess) data was tri-stated during that 24 clock cycles.


                            Allen
                          • Dave Ruske
                            ... I don t have the time to dig into it at the moment, but one thing to watch for is that the RAM at 0000 wasn t necessarily on the CPU card. My system has
                            Message 13 of 29 , Dec 13, 2003
                            • 0 Attachment
                              On Saturday, December 13, 2003, at 09:46 AM, Allen Bong wrote:
                              > I have printed and studied the 3 schematics of the ACE CPU on your
                              > cosmac elf website. I can understand how the instruction C0 pp 00
                              > was generated using the 4556. But I cant understand how the RAM
                              > (6116 I guess) data was tri-stated during that 24 clock cycles.

                              I don't have the time to dig into it at the moment, but one thing to
                              watch for is that the RAM at 0000 wasn't necessarily on the CPU card.
                              My system has some EPROM and 2K of RAM on that card, but the bulk of
                              the RAM (including page 0) is on a separate 64K dynamic RAM card. I
                              don't recall whether the data from memory was tri-stated on the CPU
                              card itself or via a signal on the bus.

                              Thanks for the reminder... I'd completely forgotten that I'd already
                              scanned in and posted those schematics!

                              Dave
                            • Allen Bong
                              ... already ... I am just lucky though. I search through all the message headers in this group and found the discussion on the ACE Bus at follows
                              Message 14 of 29 , Dec 14, 2003
                              • 0 Attachment
                                --- In cosmacelf@yahoogroups.com, Dave Ruske <dave@r...> wrote:

                                > On Saturday, December 13, 2003, at 09:46 AM, Allen Bong wrote:
                                >
                                > Thanks for the reminder... I'd completely forgotten that I'd
                                already
                                > scanned in and posted those schematics!

                                I am just lucky though. I search through all the message headers in
                                this group and found the discussion on the ACE Bus at follows

                                http://groups.yahoo.com/group/cosmacelf/message/1093

                                Do you think someone would be interested in an article in PE on an
                                article call "An 1802 based EPROM programmer"? the programmer only
                                programs 2708 eprom. If you want, I can photo-copy/scan the article
                                for your website. It is only 3 pages long in the June-81 PE.

                                Allen
                              • Stewart
                                ... Hi Allen, I for one would love to see it. Sounds like an interesting wire wrap project! And the white-gold 2708 eproms turn up on eBay regularly. They
                                Message 15 of 29 , Dec 15, 2003
                                • 0 Attachment
                                  --- In cosmacelf@yahoogroups.com, "Allen Bong" <sfbong@t...> wrote:
                                  > Do you think someone would be interested in an article in PE on an
                                  > article call "An 1802 based EPROM programmer"? the programmer only
                                  > programs 2708 eprom. If you want, I can photo-copy/scan the article
                                  > for your website. It is only 3 pages long in the June-81 PE.

                                  Hi Allen, I for one would love to see it. Sounds like an interesting
                                  wire wrap project! And the white-gold 2708 eproms turn up on eBay
                                  regularly. They are a pain with their different voltages but are
                                  certainly typical of that period in the circuits of the mid Seventies.
                                  Can you save the article as a PDF after scanning it?

                                  Stewart
                                • sfbong@tm.net.my
                                  ... From: Stewart Date: Tuesday, December 16, 2003 9:24 am Subject: [cosmacelf] 1802 eprom programmer ... Hi Stewart, I will try my best
                                  Message 16 of 29 , Dec 15, 2003
                                  • 0 Attachment
                                    ----- Original Message -----
                                    From: Stewart <stew_m_3@...>
                                    Date: Tuesday, December 16, 2003 9:24 am
                                    Subject: [cosmacelf] 1802 eprom programmer

                                    > --- In cosmacelf@yahoogroups.com, "Allen Bong" <sfbong@t...> wrote:
                                    > > Do you think someone would be interested in an article in PE on
                                    > an
                                    > > article call "An 1802 based EPROM programmer"? the programmer
                                    > only
                                    > > programs 2708 eprom. If you want, I can photo-copy/scan the
                                    > article
                                    > > for your website. It is only 3 pages long in the June-81 PE.
                                    >
                                    > Hi Allen, I for one would love to see it. Sounds like an interesting
                                    > wire wrap project! And the white-gold 2708 eproms turn up on eBay
                                    > regularly. They are a pain with their different voltages but are
                                    > certainly typical of that period in the circuits of the mid Seventies.
                                    > Can you save the article as a PDF after scanning it?
                                    >
                                    > Stewart

                                    Hi Stewart,

                                    I will try my best to scan it first. I have the Adobe PDF programs in CD but dont know which one and how to use it. But I guess I can learn. I will post it to the file section when it is ready.

                                    Allen

                                    >
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                                  • Peter de Vroomen
                                    Hi, I was browsing some old magazines yesterday (some other than I was speaking about a few weeks ago), and to my surprise there was a Microcomputing
                                    Message 17 of 29 , Jun 4 1:15 AM
                                    • 0 Attachment
                                      Hi,

                                      I was browsing some old magazines yesterday (some other than I was speaking
                                      about a few weeks ago), and to my surprise there was a 'Microcomputing'
                                      (formerly known as Kilobaud) issue with a 2716 eprom programmer based on an
                                      1802 processor.

                                      I'll scan it if there's an interest.

                                      PeterV
                                    • Michael Fogus
                                      ... I would personally love to see a scan! -m # # http://www.minotaurcomputing.com #
                                      Message 18 of 29 , Jun 4 8:47 AM
                                      • 0 Attachment
                                        > I'll scan it if there's an interest.

                                        I would personally love to see a scan!
                                        -m


                                        #
                                        # http://www.minotaurcomputing.com
                                        #
                                      • Peter de Vroomen
                                        ... Ok, the trouble was that my scanner s powersupply died, but I hacked another powersupply to work with it. So I managed to scan the pages :) (there are 2).
                                        Message 19 of 29 , Jun 6 2:22 PM
                                        • 0 Attachment
                                          > > I'll scan it if there's an interest.
                                          >
                                          > I would personally love to see a scan!

                                          Ok, the trouble was that my scanner's powersupply died, but I hacked another
                                          powersupply to work with it. So I managed to scan the pages :) (there are
                                          2).

                                          The files are in a zip file of about 3Mb. Mail me your e-mail address and
                                          I'll send it to you. Or maybe they can be hosted in cosmacelf yahoogroups?

                                          My e-mail is peterv[*at*]jaytown[*dot*]com.

                                          PeterV


                                          ---
                                          Outgoing mail is certified Virus Free.
                                          Checked by AVG anti-virus system (http://www.grisoft.com).
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                                        • david dirilo
                                          I d like the zip file. email:weenamon@yahoo.com David D. ... __________________________________ Do you Yahoo!? Friends. Fun. Try the all-new Yahoo!
                                          Message 20 of 29 , Jun 8 8:38 PM
                                          • 0 Attachment
                                            I'd like the zip file.
                                            email:weenamon@...
                                            David D.
                                            --- Peter de Vroomen <peterv@...> wrote:
                                            > > > I'll scan it if there's an interest.
                                            > >
                                            > > I would personally love to see a scan!
                                            >
                                            > Ok, the trouble was that my scanner's powersupply
                                            > died, but I hacked another
                                            > powersupply to work with it. So I managed to scan
                                            > the pages :) (there are
                                            > 2).
                                            >
                                            > The files are in a zip file of about 3Mb. Mail me
                                            > your e-mail address and
                                            > I'll send it to you. Or maybe they can be hosted in
                                            > cosmacelf yahoogroups?
                                            >
                                            > My e-mail is peterv[*at*]jaytown[*dot*]com.
                                            >
                                            > PeterV
                                            >
                                            >
                                            > ---
                                            > Outgoing mail is certified Virus Free.
                                            > Checked by AVG anti-virus system
                                            > (http://www.grisoft.com).
                                            > Version: 6.0.698 / Virus Database: 455 - Release
                                            > Date: 2-6-2004
                                            >
                                            >





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