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Thread: M847 extended edition > Bootloader in PDP style !

  1. #31
    Join Date
    Jul 2014
    Rhode Island


    Looks like you have the bootstraps covered.
    Member of the Rhode Island Computer Museum

  2. #32


    Quote Originally Posted by m_thompson View Post
    Looks like you have the bootstraps covered.
    Thanks for checking!

    I've added the Digikey order numbers to the part list. You can find them
    in the "M847 extended version V1.1 component list Digikey.xls" at Github.

    There are 4 parts not needed to place. Just optional, I've noted that in the list as well...
    If you place all the parts (without the not needed parts) the total is $26.98

    To be honest, it would be great if Digikey could sell the ATMEGA328 with the Arduino bootloader in it.
    I've put in the bootloader myself with another Arduino board. I can make a little tutorial on how to do that.

    But you can buy them programmed here in electronic shops for just a little more than the not
    programmed versions. And you can get them programmed at Ebay as well under $2...

    Flashing the bootloader is just a one time action. After that you can
    upload the M847 firmware trough the serial port on the board.

    Regards, Roland
    Last edited by Roland Huisman; November 11th, 2018 at 12:22 PM.
    WTB: Case for Altair 8800 ...... Rolands Github projects

  3. #33
    Join Date
    Nov 2018
    Galveston, Texas


    I too would like one or two boards to complement my PDP8/E. I can handle the hardware side, but the software and flashing part would be more challenging for me. Using a BC01V is good for me...


  4. #34


    Hi Matt,

    Great! Then I will make a video and documentation of how to flash the
    bootloader and load in the .ino firmware file. It's really easy to do...

    Regards, Roland
    WTB: Case for Altair 8800 ...... Rolands Github projects

  5. #35

    Default Additions to m847 board

    Dear all,

    I have just registered with this group.

    Briefly I am a retired doctor with four pdp8e, none of which work (I had two working 30 years ago), a pdp8L, and an Elliott 920 ? only one still complete and in existance with documentation; I had it working up to 1986. I had got bored during my clinical medical training so designed and built a rather slow 16 bit computer using dtl
    integrated circuits. I had also played with a pdp8s and an ibm 1630 during my preclinical student years.

    So, I know a bit about radio and electronics, up to but not including microprocessors, but my home brew 16 bit machine was useless as I could not do any significant programming. I hope to get some of these dec machines going, along with rk05 dectape etc although time still appears to be in short supply. Bletchley Park wants the Elliott 920.

    Back to subject..........

    Is there any interest/will to include a serial port drive on the board, complete with sd or compact flash card emulating a drive through the serial interface? I suppose the serial drive i/o would have to loop back to a serial card on the omnibus, but the system would then not need a laptop running to supply the data to the serial port.

  6. #36


    Dear All,

    I have just registered to this forum, with much difficulty. My first attempt was erased because I ceased typing for a few minutes as someone was at the door and I was looged out, losing my whole message.

    So I will be brief.

    An addition to the 847 board could include a server ( ? Using the existing pic ) to supply images stored on a sd card, of rk05 drives or dectape to a serial output to connect to an omnibus serial card, thus providing an internal serial disk. This would save having a laptop doing the same job.

    Stephen Laurence (4 non- functional pdp8/e a non functional pdp8/L and an Elliott 920a)

  7. #37


    Hi Stephen,

    Welcome to this forum and thanks for your input I think it would
    be nice to show pictures of your Elliott 920a under the Pre Aitair machines.

    There are many projects for the PDP8 machines. One of them is Kyle Owens OS8 disk server.
    I had this running on an old laptop in my demo. But you can put in a Raspberry Pi in your PDP as well.
    It gives you the complete emulated RK05 experience. Philipp Hachtmann designed a very fast
    serial USB Omnibus card for these machines. With this card you can speed up the disk server.

    But with just two serial cards, 8K of memory in the PDP and a Linux based computer
    (Pi Laptop, doesn't matter) with OS8 disk server you can run OS8.

    Regards, Roland
    WTB: Case for Altair 8800 ...... Rolands Github projects

  8. #38

    Default Pdp8 internal virtual disk and Elliott920a

    Dear Roland,

    Thankyou for the welcome. I actually did Part2 Electrical Sciences after my medical preclinical studies and had planned to persue medical electronics, but a bit later in my anaesthetic training when I tried to work in industry for a while, no-one was interested, despite the boom in medical monitoring in the 1970s, so I became a consultant anaesthetist and kept the electronics interest as a hobby.

    The Elliott came out of a rubbish skip. I had it working in 1980 until 1986. No disk or anything, programmes loaded with paper tape whizzing through and collected in a dustbin prior to rewinding. 100 blinking lights. Heated the room nicely.

    It is currently behind a load of other electronic junk so I cannot take a decent picture of it. As it has not been powered up for 32 years, it will have to be powered with a Variac to reform the psu capacitors ( psu is 2 cubic ft box on the floor).

    After a break of a year, I am going to attack the PDP8 machines again to get one or more working. I have a 32kw ram board built but untested, boards from four machines, scopes, meters, chip-level logic tester etc but no Linux or RasbPi experience. My programming experience is Focal, Basic, rusty Fortran etc from 40 years ago but no machine level code.

    Lots to do and a new wife to keep happy (much harder work than a faulty pdp.

    Steve Laurence

  9. #39
    Join Date
    Jun 2012
    UK - Worcester


    Welcome to VCFED Stephen.

    If you are looking to get your 8's going - you've come to the right place. A few people 'lurk' here who have done just that...

    Where are you based?


  10. #40

    Default My location

    Dear David,

    My location is Preston Lancs, so about 130 miles and a dreadful drive down the M6.

    I had another quick go with the 8's this afternoon. There must be 100s of faults. i have the three cpu cards from four 8/e machines and two front panels, and every card combination gives different issues. I cannot even get the pc to increment or load an address, let alone read any address. So much for hoping at least one of each card would still work.

    Next, I will pull every card except the front panel, three cpu cards and the bus terminator to try and get some sense of what dozens of faults might be on these cards.

    I have a 32kw memory card which I obviously have not been able to test, but if Inhave not screwed up my soldering or blown some chips plugging them in, I suppose I can assume it will work.

    Stephen L


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