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Re: [cosmacelf] Re: Tiny ELF, ELF2K, EELF2K, Membership Card. Which to choose...

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  • J.C. Wren
    The point is neither speed nor power, but the ability to add and remove peripherals without altering the hardware. It also gives a large amount of I/O without
    Message 1 of 40 , Sep 29, 2009
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      The point is neither speed nor power, but the ability to add and remove
      peripherals without altering the hardware. It also gives a large amount of
      I/O without wiring up dozens of 1853's.
      Another reason is simply because it's taking some of the oldest technology
      and combining it with some of the newest. Sort of like surface mount and
      nixie tubes.

      I'd really like to have a little board that I could drop most any processor
      core into (1802, MSP430, AVR, Z80) for whatever reason. As much as I like
      building hardware, I get tired of scrounging up hardware when the mood hits
      me to play with something different. It also makes starting with a clean
      slate each time much easier.

      --jc

      On Mon, Sep 28, 2009 at 11:41 PM, Lee Hart <leeahart@...> wrote:

      > jporubek wrote:
      > > I, too, would like to see a VHDL implementation of the 1802. I've
      > > often thought that the 1802's simple architecture would provide a good
      > > training exercise in coding micros in VHDL. Add something like Bob
      > > Armstrong's PLD version of the 1861
      > > (http://www.sparetimegizmos.com/Hardware/Elf2K_Accessories.htm#STG1681
      > > Pixie Graphics Replacement) and some basic auxiliary hardware support
      > > and you would have a micro that could actually do something and has
      > > software available for it, unlike the hypothetical processors often
      > > created for such exercises.
      >
      > While it's an interesting project from a technical point of view, what
      > would be the intended application?
      >
      > The real 1802 is still available, and likely to use far less power than
      > a gate array programmed to emulate an 1802.
      >
      > The gate array could be much faster; but if speed is the issue, there
      > are better architectures. (The 1802 takes 16 to 24 clock cycles per
      > instruction).
      >
      > Personally, I like the simplicity of the 1802. So my goal would be to
      > find a way to use even less hardware to do the same job. A brilliant
      > step in that direction was the 8-pin PIC that someone (I forget who)
      > programmed to emulate not just the 1802 but the entire ELF! Moving in
      > that direction, could one develop a serial bus version of the 1802
      > architecture, where one 8-pin chip is the 1802, another is the 1861 (for
      > video output), another is the memory (using standard serial memory
      > chips), and some serial-to-parallel chips for general I/O ports?
      > --
      > Lee A. Hart | Ring the bells that still can ring
      > 814 8th Ave N | Forget the perfect offering
      > Sartell MN 56377 | There is a crack in everything
      > leeahart earthlink.net | That's how the light gets in -- Leonard Cohen
      >
      >
      > ------------------------------------
      >
      > ========================================================
      > Visit the COSMAC ELF website at http://www.cosmacelf.comYahoo! Groups
      > Links
      >
      >
      >


      [Non-text portions of this message have been removed]
    • eight_bit_jdrose
      CamelForth looks interesting. It seems to be designed specifically for small implemented microcomputers. I was looking at the source and it seems to be really
      Message 40 of 40 , Feb 16, 2013
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        CamelForth looks interesting. It seems to be designed specifically for small implemented microcomputers.

        I was looking at the source and it seems to be really well written code. It is documented well and has a number of nifty additional WORDS including some debugging ones.

        --- In cosmacelf@yahoogroups.com, jporubek <jporubek@...> wrote:
        >
        > Very good summary of the current state of the hobbyist micro world,
        > Mark. I'm usually a lurker in this group, but I couldn't resist the
        > urge to weigh in with my opinions.
        >
        > I, too, don't particularly care for PIC micros and I'm not entirely
        > sure why. Maybe it's because the original chips had next to no
        > hardware support for a decent stack. I'm a big fan of programming in
        > Forth for micros, and you can't do Forth without a real stack. Or
        > maybe it was the weird, non-standard assembly language mnemonics,
        > especially if you were used to the 6502/6800 style of mnemonics (or
        > even 808x mnemonics). I know that PICs have come a long way since
        > those early days, but I still feel a small sense of disappointment
        > when I read an article in Circuit Cellar and discover that the project
        > is based on a PIC. It's also a big reason why I keep telling myself
        > I'm going to let my subscription to Nuts and Volts run out next time
        > it's due.
        >
        > Like most people in this group, I got my start in micros with the RCA
        > 1802, building my own improved version of the ELF with muxed data AND
        > address displays and a hex keypad. I was enamored with all things
        > COSMAC and acquired a VIP, a Studio II, and even an RCA Micromonitor.
        > I then progressed to 6502-based computers with an AIM-65 and a
        > Commodore 64 before assembling my first PC. I dabbled a little with
        > the 8085 via a Radio Shack Model 100 and a Kyocera 85. I'd like to get
        > back to all of them someday as part of my own mini-museum - maybe if I
        > can ever retire!
        >
        > I like AVRs from what I've read about them, although I don't have any
        > hands-on experience. A brief professional exposure to an 8051 project
        > was painful, although this may not have been the 8051's fault - it was
        > being over-taxed with bank-switched memory and the code I had to
        > interface with was badly-written C spaghetti code. I have mostly
        > pleasant experiences with 68HC05s, 680x0s and Coldfires.
        >
        > However, my current processor of choice is the TI MSP430. In some ways
        > it could be claimed to be the cultural descendant of the 1802. Like
        > the 1802, the MSP430 is designed for low-power applications, although
        > modern semiconductor process technologies make the MSP430 a far lower
        > power device than the 1802 could ever have hoped to have been. Like
        > the 1802, the MSP430 architecture is based on 16 16-bit registers,
        > although the program counter and stack pointer registers are fixed for
        > the MSP430, unlike the 1802! There are versions of Forth available for
        > both the MSP430 and the 1802 at http://www.camelforth.com There's
        > even a version there that I ported for the TI eZ430-RF2500T low-cost
        > USB stick development tool.
        >
        > Mark, your website looks really interesting, especially your
        > 8085-based micro trainer. I plan to spend some spare time looking
        > through all that's available there. Thanks for putting it up on the
        > web!
        >
        > --John
        >
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