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  • daver2's Avatar
    Yesterday, 01:02 PM
    daver2 replied to a thread D.R.E.A.M. 6800 Build in Other
    I have the assembler listing file for it - that is what I am currently typing in. I have tried OCRing it - but no dice (even a nice PDF copy I...
    22 replies | 765 view(s)
  • daver2's Avatar
    Yesterday, 11:58 AM
    daver2 replied to a thread D.R.E.A.M. 6800 Build in Other
    But do you have the source code for it that you can assemble rather than just the BIN/HEX/SREC? Dave
    22 replies | 765 view(s)
  • daver2's Avatar
    Yesterday, 11:49 AM
    daver2 replied to a thread D.R.E.A.M. 6800 Build in Other
    Forgot to say - I am typing in the source code for the CHIP8 interpreter from the source code listing. It was too complex for OCR - but I may have...
    22 replies | 765 view(s)
  • daver2's Avatar
    Yesterday, 11:36 AM
    Give me a couple of days (another business trip coming up) and I will post my thoughts on what I think the issue could be. When you are ready to...
    64 replies | 1034 view(s)
  • daver2's Avatar
    Yesterday, 11:32 AM
    daver2 replied to a thread D.R.E.A.M. 6800 Build in Other
    >>> in that it’s that small AND single sided. Incredible use of jumpers, making it possible for hobbyists to etch the board at home easily. Very...
    22 replies | 765 view(s)
  • daver2's Avatar
    Yesterday, 11:25 AM
    Open it up and get the vacuum cleaner on it - the suction hose that is; not the brushes :-)! Dave
    8 replies | 128 view(s)
  • daver2's Avatar
    Yesterday, 11:18 AM
    daver2 replied to a thread D.R.E.A.M. 6800 Build in Other
    I notice over on the microbee site that someone is recreating the 6800/6802 DREAM CPU, KEYPAD and PSU PCBs. I will try and send them an e-mail to...
    22 replies | 765 view(s)
  • daver2's Avatar
    Yesterday, 11:14 AM
    Sorry I haven't got around to relying to your PMs - a few personal/work related items to take care of at the moment. I live in the UK - so...
    26 replies | 1133 view(s)
  • daver2's Avatar
    January 13th, 2019, 11:12 PM
    The Z80 CPU reset pin is a power on reset. The switch marked RESET actually drives the Z80 NMI pin. If the BOOT ROM is not working properly, it...
    27 replies | 879 view(s)
  • daver2's Avatar
    January 13th, 2019, 10:55 PM
    Yep, this fault is a doozy! I have a few more ideas now I have had a think overnight. But I agree with VERAULT - let's have a couple of days off...
    64 replies | 1034 view(s)
  • daver2's Avatar
    January 13th, 2019, 01:20 PM
    Hmmmmm... This solves why this problem is being such a pain! So, (to sum up) you have two keyboards. The original keyboard had (we believe) a...
    64 replies | 1034 view(s)
  • daver2's Avatar
    January 13th, 2019, 11:58 AM
    Good idea. I will have a cup of coffee then... Dave
    64 replies | 1034 view(s)
  • daver2's Avatar
    January 13th, 2019, 11:44 AM
    The 'Best' sounds the best (!) set to a 20k range I think. With the polarised keyboard ribbon cable connected at one end to the keyboard connector...
    64 replies | 1034 view(s)
  • daver2's Avatar
    January 13th, 2019, 11:34 AM
    >>> Appreciate this.. No problem at all. >>> did you use some kind of software to do it? Yes. If you remember I disassembled the character...
    27 replies | 879 view(s)
  • daver2's Avatar
    January 13th, 2019, 11:04 AM
    Excellent. The next thing (as you have correctly pointed out) is that your problems seem to start when you connect the physical keyboard up to the...
    64 replies | 1034 view(s)
  • daver2's Avatar
    January 13th, 2019, 10:58 AM
    Here is a binary file that I created from the two BOOT EPROMS you posted. The two EPROMS are combined into a single binary file. ...
    27 replies | 879 view(s)
  • daver2's Avatar
    January 13th, 2019, 09:48 AM
    daver2 replied to a thread D.R.E.A.M. 6800 Build in Other
    I definitely want 6 lottery numbers from you! Dave
    22 replies | 765 view(s)
  • daver2's Avatar
    January 13th, 2019, 08:43 AM
    daver2 replied to a thread D.R.E.A.M. 6800 Build in Other
    Dog's sniff out truffles - Falter sniffs out unbuilt vintage PCBs :-)! Any chance of you picking the lottery numbers for me this week! Dave
    22 replies | 765 view(s)
  • daver2's Avatar
    January 13th, 2019, 08:39 AM
    >>> Here we go - the only "closed circuit" is between J and K. No other pair of pins shows continuity. Excellent news, that was what we were...
    64 replies | 1034 view(s)
  • daver2's Avatar
    January 13th, 2019, 06:06 AM
    The keyboard pins on the keyboard itself (for both questions). What we are trying to demonstrate/prove is that the physical keyboard itself...
    64 replies | 1034 view(s)
  • daver2's Avatar
    January 13th, 2019, 05:40 AM
    >>> One point to remember: the "repeated t's" issue existed with the previous keyboard also. That was what I was going to get onto next... >>>...
    64 replies | 1034 view(s)
  • daver2's Avatar
    January 13th, 2019, 03:53 AM
    A good nights sleep! There are a few things in the post above - so I would like to take them one at a time if I may. I think measuring the...
    64 replies | 1034 view(s)
  • daver2's Avatar
    January 13th, 2019, 12:14 AM
    daver2 replied to a thread D.R.E.A.M. 6800 Build in Other
    I am constantly amazed at how you "sniff out" boards like this! I have come across CHIPOS/CHIP8 before. I wonder if I can make a variant for this...
    22 replies | 765 view(s)
  • daver2's Avatar
    January 12th, 2019, 03:06 PM
    So, going all the way pack to posts 1 and 2 of this thread you stated that when you did the <RETURN> boot trick with CP/M without the keyboard/cable...
    64 replies | 1034 view(s)
  • daver2's Avatar
    January 12th, 2019, 02:25 PM
    That's one way of looking at it. However, touching your voltmeter on pins 7 and 8 of UE12 - and the machine going 'screwy' in both cases is not...
    64 replies | 1034 view(s)
  • daver2's Avatar
    January 12th, 2019, 01:46 PM
    OK, so let's take things a bit more slowly... The answer to your booting from Drive 'B' can be found with google over at...
    64 replies | 1034 view(s)
  • daver2's Avatar
    January 12th, 2019, 12:45 PM
    >>> As I said in post #21, I already found that IC and did the pin voltage checks. Not sure why you're just now pointing out where the IC is. ...
    64 replies | 1034 view(s)
  • daver2's Avatar
    January 12th, 2019, 12:43 PM
    Thanks - so you have tried multiple cables (3 off) and 2 keyboards - so we should be able to rule out a cable fault. What I am trying to do here...
    64 replies | 1034 view(s)
  • daver2's Avatar
    January 12th, 2019, 12:33 PM
    If you look at the image here https://www.techrepublic.com/pictures/cracking-open-the-osborne-1-the-original-portable-computer/34/, UE12 is just to...
    64 replies | 1034 view(s)
  • daver2's Avatar
    January 12th, 2019, 12:24 PM
    I am suspecting a fault within UE12 (81LS95) - but before we jump to that conclusion I want to rule out a few things. I want to first checkout that a...
    64 replies | 1034 view(s)
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About daver2

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SW/HW design engineer

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