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Re: [cosmacelf] Re: 2N2222 ++ 1N914 DTL (off topic)

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  • David Keith
    A couple months ago I was recovering from double knee replacements (6 weeks apart) I had a lot of time on my hands that I could not work, I have been doing a
    Message 1 of 25 , Apr 17, 2013
    A couple months ago I was recovering from double knee replacements (6 weeks apart) I had a lot of time on my hands that I could not work,  I have been doing a lot experimenting with Diode Transistor Logic for a while now, so I decided to design a PCB and have some madeDTL is much easier and cost effective than a pure transistor circuit.  I decided to redesign an IBM SMS card using today's discreet components LOL.(I was on some very good drugs)  The original only SMS card I have contained 6 NAND circuits, while my new design uses 48 AOI (and-or-invert) gates (I prefer AOIs because I can design much tighter logic, with much less transistors). I have attached several pictures, of comparing the SMS basic form to my AOI board.  With another with a card almost populated, The last is the layout showing a 1 bit-slice CPU with 8 registers, full functional ALU (74181 equivalent), and data register to memory interface.  Overall it was just something to do that was not work related.  I plan to populate a board a month to get an 8-bit CPU/ALU core.

    --David Keith


    From: Lee Hart <leeahart@...>

    On 4/17/2013 8:14 PM, jdrose_8_bit wrote:
    >
    >> --- In cosmacelf@yahoogroups.com, David Keith
    >>
    >>  I proposed the ISA committee so we as a group of 1802
    >> assembler programmers can have a common future version to use and share.
    >>
    >>  There are many ways to implement it, and several have already
    >> been done by this group. I believe even Lee suggested implementing an
    >> 1802 using fet transistors :-)  a month or so back.

    >> What are the differences between "regular" 2N2222 transistors and Field Effect transistors when implementing logic gates?

    >You can built the same sort of circuits with either type, but the
    >details of the circuit are quite different. Compare the internal
    >schematic for a bipolar gate (7400 etc.) which is built with bipolar
    >transistors, to that of a CMOS gate (4011 etc. built with MOSFETs. (The
    >internal circuits are on the older data sheets.)

    >If you wanted to build an 1802 from individual transistors, n-channel
    >and p-channel MOSFETs would work with exactly the same circuits used in
    >the 1802. The MOSFETs would cost you around 5-10 cents each.

    >If you wanted to build an 1802 with bipolar transistors, you would have
    >to replace each type of gate (inverter, NAND, NOR, flip-flop, etc.) with
    >its equivalent bipolar circuit. It would wind up requiring more
    >transistors and be faster; but use more power. Bipolar transistors are
    >3-5 cents each, but you'd need more of them so the price probably comes
    >out about the same.


    --
  • bill rowe
    Keith: what does the card do? To: cosmacelf@yahoogroups.com From: beloved_wind@yahoo.com Date: Wed, 17 Apr 2013 21:19:46 -0700 Subject: Re: [cosmacelf] Re:
    Message 2 of 25 , Apr 18, 2013
    • 0 Attachment
      Keith: what does the card do?


      To: cosmacelf@yahoogroups.com
      From: beloved_wind@...
      Date: Wed, 17 Apr 2013 21:19:46 -0700
      Subject: Re: [cosmacelf] Re: 2N2222 ++ 1N914 DTL (off topic) [4 Attachments]

       
      [Attachment(s) from David Keith included below]
      A couple months ago I was recovering from double knee replacements (6 weeks apart) I had a lot of time on my hands that I could not work,  I have been doing a lot experimenting with Diode Transistor Logic for a while now, so I decided to design a PCB and have some madeDTL is much easier and cost effective than a pure transistor circuit.  I decided to redesign an IBM SMS card using today's discreet components LOL.(I was on some very good drugs)  The original only SMS card I have contained 6 NAND circuits, while my new design uses 48 AOI (and-or-invert) gates (I prefer AOIs because I can design much tighter logic, with much less transistors). I have attached several pictures, of comparing the SMS basic form to my AOI board.  With another with a card almost populated, The last is the layout showing a 1 bit-slice CPU with 8 registers, full functional ALU (74181 equivalent), and data register to memory interface.  Overall it was just something to do that was not work related.  I plan to populate a board a month to get an 8-bit CPU/ALU core.

      --David Keith


      From: Lee Hart <leeahart@...>

      On 4/17/2013 8:14 PM, jdrose_8_bit wrote:
      >
      >> --- In cosmacelf@yahoogroups.com, David Keith
      >>
      >>  I proposed the ISA committee so we as a group of 1802
      >> assembler programmers can have a common future version to use and share.
      >>
      >>  There are many ways to implement it, and several have already
      >> been done by this group. I believe even Lee suggested implementing an
      >> 1802 using fet transistors :-)  a month or so back.

      >> What are the differences between "regular" 2N2222 transistors and Field Effect transistors when implementing logic gates?

      >You can built the same sort of circuits with either type, but the
      >details of the circuit are quite different. Compare the internal
      >schematic for a bipolar gate (7400 etc.) which is built with bipolar
      >transistors, to that of a CMOS gate (4011 etc. built with MOSFETs. (The
      >internal circuits are on the older data sheets.)

      >If you wanted to build an 1802 from individual transistors, n-channel
      >and p-channel MOSFETs would work with exactly the same circuits used in
      >the 1802. The MOSFETs would cost you around 5-10 cents each.

      >If you wanted to build an 1802 with bipolar transistors, you would have
      >to replace each type of gate (inverter, NAND, NOR, flip-flop, etc.) with
      >its equivalent bipolar circuit. It would wind up requiring more
      >transistors and be faster; but use more power. Bipolar transistors are
      >3-5 cents each, but you'd need more of them so the price probably comes
      >out about the same.


      --

    • jdrose_8_bit
      Thank you. Great explanation. I knew how bipolar transistors worked but FETs were a mystery to me.
      Message 3 of 25 , Apr 18, 2013
      • 0 Attachment
        Thank you. Great explanation. I knew how bipolar transistors worked but FETs were a mystery to me.

        --- In cosmacelf@yahoogroups.com, Lee Hart <leeahart@...> wrote:

        > >
        > > What are the differences between "regular" 2N2222 transistors and Field Effect transistors when implementing logic gates?
        >
        > Quite a bit! Bipolar transistors are current-controlled; a current into
        > the base (at negligible voltage) turns them on. FETs (including MOSFETs)
        > are voltage-controlled; a voltage into the gate (at negligible current)
        > turns them on.
        >
        > You can built the same sort of circuits with either type, but the
        > details of the circuit are quite different. Compare the internal
        > schematic for a bipolar gate (7400 etc.) which is built with bipolar
        > transistors, to that of a CMOS gate (4011 etc. built with MOSFETs. (The
        > internal circuits are on the older data sheets.)
        >
        > If you wanted to build an 1802 from individual transistors, n-channel
        > and p-channel MOSFETs would work with exactly the same circuits used in
        > the 1802. The MOSFETs would cost you around 5-10 cents each.
        >
        > If you wanted to build an 1802 with bipolar transistors, you would have
        > to replace each type of gate (inverter, NAND, NOR, flip-flop, etc.) with
        > its equivalent bipolar circuit. It would wind up requiring more
        > transistors and be faster; but use more power. Bipolar transistors are
        > 3-5 cents each, but you'd need more of them so the price probably comes
        > out about the same.
        >
        > Either way, it would be a major project; like building a model Eiffel
        > tower out of toothpicks. :-)
        >
        >
        > Lee A. Hart, http://www.sunrise-ev.com/LeesEVs.htm
        >
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