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Hardware emulation with the Propeller — Parallax Forums

Hardware emulation with the Propeller

Nu World NetworkNu World Network Posts: 21
edited 2009-06-13 13:35 in Propeller 1
I recently ordered a book called Apple I Replica Creation: Back to the Garage. I have not received it yet, but I have seen some schematics for the Apple I in the past. I was wondering if it would be possible to emulate most of the components with one or two Propellers. I have a 6502 clone (65c02) that I bought for a failed project two years ago, and the Apple I ran on a MOS 6502. Does anyone think that this is possible?

Comments

  • trodosstrodoss Posts: 577
    edited 2009-06-05 14:28
    @Nu World Network,

    That sounds like an interesting book!

    There is a project going on to emulate the 6502 on the Propeller (don't know if it is still active).· You will have to 'skip ahead' in the thread to see the mention of the 6502 emulation. [noparse][[/noparse]Edit:] I think their goal is to run the entire emulation off of a single Propeller.

    http://forums.parallax.com/showthread.php?p=767703



    If you were planning on using the·Prop just to handle I/O, and are looking for just the TV driver, Baggers had posted an Apple ][noparse][[/noparse]·TV driver from the above mentioned project:

    http://forums.parallax.com/showthread.php?p=782933


    [noparse][[/noparse]Edit:] I would think that the only other hurdle would be to get a working tape interface.· I know there is a C64 Datacasette emulation project, which if anything, you might borrow some of the approach:

    http://forums.parallax.com/showthread.php?p=695936

    Post Edited (trodoss) : 6/5/2009 2:39:54 PM GMT
  • Oldbitcollector (Jeff)Oldbitcollector (Jeff) Posts: 8,091
    edited 2009-06-05 14:31
    Vince Briel actually used a Propeller in his Replica 1.

    So yes, the Propeller is perfect for this. Hopefully we'll have
    some 6502 emulation soon as well!

    OBC

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  • potatoheadpotatohead Posts: 10,261
    edited 2009-06-05 14:43
    6502 is active -- I'm just needing to do some learning before I continue that project. Heater has really pushed the envelope on CPU emulation. See the Zicog project running CP/M for what is possible. (and that one is damn cool!)

    The propeller appears to be quick enough to do a 1Mhz+6502. That would put an Apple I within striking range.

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  • trodosstrodoss Posts: 577
    edited 2009-06-05 14:45
    I had forgotten about the PROP-6502 Propeller Laptop (Dennis Ferron)
    http://www.parallax.com/tabid/708/Default.aspx
  • Nu World NetworkNu World Network Posts: 21
    edited 2009-06-05 17:44
    Well, the idea was to emulate most of the components on the Apple I board, so that it would be fully compatible (or at least as compatible as the Replica I). I also was hoping I could build it cheaper than the Replica I.

    Post Edited (Nu World Network) : 6/5/2009 5:50:27 PM GMT
  • waltcwaltc Posts: 158
    edited 2009-06-05 18:26
    Nu world,

    If you are just interested in emulating the components of a Apple I board you might consider using a couple of CPLD's like the Altera Max II. CPLD's are perfect for that.
  • Nu World NetworkNu World Network Posts: 21
    edited 2009-06-06 23:56
    waltc said...
    Nu world,

    If you are just interested in emulating the components of a Apple I board you might consider using a couple of CPLD's like the Altera Max II. CPLD's are perfect for that.

    Yeah, but CPLDs are about 30-40 dollars each.
  • Nu World NetworkNu World Network Posts: 21
    edited 2009-06-07 00:54
    I have been looking at some Z80 based systems and I have a quick question: Can CPLDs serve as several components at once?
  • Bill HenningBill Henning Posts: 6,445
    edited 2009-06-07 01:08
    yes, and the Xilinx XC9536 and XC9572 are affordable.
    Nu World Network said...
    I have been looking at some Z80 based systems and I have a quick question: Can CPLDs serve as several components at once?
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  • hinvhinv Posts: 1,255
    edited 2009-06-07 02:21
    As a side note, what is the difference between a PAL and a CPLD?

    Thanks,
    Doug
  • Bill HenningBill Henning Posts: 6,445
    edited 2009-06-07 03:09
    basically more gates and pins, and usually more sophisticated logic elements
    hinv said...
    As a side note, what is the difference between a PAL and a CPLD?

    Thanks,
    Doug
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  • Nu World NetworkNu World Network Posts: 21
    edited 2009-06-07 18:42
    Another quick question: I have found a pretty good SBC design to try instead of the Apple I. Most of the components are easy to obtain. However, some transistors are virtually impossible to find anywhere:

    2N5375
    1N4001 (Found It)
    1N914 (Found It)
    2N5371

    Does anyone know where to find these? Or are there similar components available?

    Post Edited (Nu World Network) : 6/7/2009 6:50:07 PM GMT
  • Mike GreenMike Green Posts: 23,101
    edited 2009-06-07 19:15
    Here are datasheet links:

    2n5371 www.americanmicrosemi.com/information/spec/?ss_pn=2N5371

    2n5375 www.americanmicrosemi.com/information/spec/?ss_pn=2N5375

    Look for similar transistors. You want to roughly match collector current (Ic), gain (hFE), power dissipation, and switching frequency (fT). Obviously, the transistor will need to be of the same type (PNP / NPN, Junction / MOSFET). The pinouts and packaging may be different, but often you can bend the leads to fit.

    The 2N5371 seems to be a general purpose NPN switching transistor while the 2N5375 is a roughly matching PNP switching transistor.

    You might be able to get by with a 2N3604 for the 2N5375 and a 2N3606 for the 2N5371. RadioShack carries NPN and PNP switching transistors that probably will work and TV repair parts suppliers also carry similar parts.

    Post Edited (Mike Green) : 6/7/2009 7:22:28 PM GMT
  • Nu World NetworkNu World Network Posts: 21
    edited 2009-06-07 19:53
    Thank you! That info is really helpful.
  • Nu World NetworkNu World Network Posts: 21
    edited 2009-06-10 13:23
    A Static RAM chip I need is proving very hard to find at any online electronics store (Jameco, Digikey, etc.) I am trying to find a similar chip. What type of specifications should I focus on when finding a new chip?
  • LeonLeon Posts: 7,620
    edited 2009-06-10 13:26
    Which SRAM?

    Leon

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  • Nu World NetworkNu World Network Posts: 21
    edited 2009-06-10 13:37
    The SRM20256LC Static RAM chip. Only Large-Order distributors seem to sell it.
  • LeonLeon Posts: 7,620
    edited 2009-06-10 14:02
    I think it's obsolete. I'd choose something else that is easier to buy.

    Leon

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  • Nu World NetworkNu World Network Posts: 21
    edited 2009-06-10 14:18
    Leon said...
    I think it's obsolete. I'd choose something else that is easier to buy.

    Leon

    That is exactly what my question was about. What specifications should I focus on when finding the new chip, to make it as compatible as possible.
  • Toby SeckshundToby Seckshund Posts: 2,027
    edited 2009-06-10 14:19
    A quick look at its datasheet shows it is nothing special. The pinouts are the same as a generic 28 pin 32KB sram, with 100 or 120nS access
    pdf
    pdf
    datasheet.pdf
    170K
  • Nu World NetworkNu World Network Posts: 21
    edited 2009-06-10 14:24
    Thanks Toby.
  • kwinnkwinn Posts: 8,697
    edited 2009-06-10 14:55
    If you are using 2 ram chips for 64K you may want to get one larger (64K/128K) chip instead.
  • Toby SeckshundToby Seckshund Posts: 2,027
    edited 2009-06-10 15:24
    Yes, if you can afford the extra pin count on the layout. They are usually no more money and give the luxury of expansion/paging for free. Battery backup it and there is some non volatile storage, with no write limits. For new stuff I use 128Kb, but being a horder, I have a bunch of 32Kb pulls.

    Old stuff with reasonable chips, in bases, is rare now. cry.gif
  • Nu World NetworkNu World Network Posts: 21
    edited 2009-06-12 14:52
    Hey guys! Sorry to bring back a dead thread, but I just pushed the final chip into its socket (a 556 timer)! I'll post some pictures as soon as I get a program running.
  • Toby SeckshundToby Seckshund Posts: 2,027
    edited 2009-06-13 13:35
    It isn't a dead thread after a few days! but it might die because it has fallen off the front page.

    I tried to put a sort of minimal Nascom1 together and used a 555 for the Baud rate genny, drifted like ...
    Overkill or not I put in an AVR just looping around. It gave 19.2K .... rates all the way down to 300 Baud, as a bonus. Binned that bd along time ago and now should complete the "Z80 nailed to a prop"
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