Image Map Image Map
Tab Content
  • daver2's Avatar
    Today, 02:31 PM
    daver2 replied to a thread Sick SuperPET in Commodore
    Yep, you're correct. What goes IN on the 'A' side should come out (completely unmodified) on the 'BA' side. I suspect this will be the case though...
    165 replies | 6223 view(s)
  • daver2's Avatar
    Today, 11:11 AM
    daver2 replied to a thread Sick SuperPET in Commodore
    It's sounding more and more like a ROM fault to me the more you investigate... It is, however, somewhat weird to see a single ROM socketed (U49)....
    165 replies | 6223 view(s)
  • daver2's Avatar
    Today, 01:16 AM
    The PCB layout is available from his website. You download it (plus a copy of expresspcb - also free) and you can order a 1 off PCB for the unit. ...
    32 replies | 464 view(s)
  • daver2's Avatar
    Today, 12:02 AM
    daver2 replied to a thread Sick SuperPET in Commodore
    The reason you can't find a design on the internet is that one doesn't exist yet! As the Commander has said, the design will be identical to the...
    165 replies | 6223 view(s)
  • daver2's Avatar
    Yesterday, 12:12 PM
    daver2 replied to a thread Sick SuperPET in Commodore
    I have just edited the text of post #148 which should make the reset situation a bit more clear. There seems to have been a flurry of overlapping...
    165 replies | 6223 view(s)
  • daver2's Avatar
    Yesterday, 12:01 PM
    daver2 replied to a thread Sick SuperPET in Commodore
    Just want to attribute the idea about using an unused ROM socket to the correct 'owner' MikeS. I would be inclined to order the bits for the 6809...
    165 replies | 6223 view(s)
  • daver2's Avatar
    Yesterday, 12:33 AM
    daver2 replied to a thread Sick SuperPET in Commodore
    Using the negative terminal of the large capacitor should guarantee a good connection. This terminal should also be directly connected to the metal...
    165 replies | 6223 view(s)
  • daver2's Avatar
    February 17th, 2017, 08:32 AM
    daver2 replied to a thread Sick SuperPET in Commodore
    Always better to have things in 'stereo' KC9UDX! So you've built your own 6502 NOP generator. You can use the same technique to make a 6809 NOP...
    165 replies | 6223 view(s)
  • daver2's Avatar
    February 17th, 2017, 07:47 AM
    daver2 replied to a thread Sick SuperPET in Commodore
    Glad to hear that Dave solved your 2K ROM issue and your RAM is now working. One (more) thing we can tick off the list that it is not! Please be...
    165 replies | 6223 view(s)
  • daver2's Avatar
    February 17th, 2017, 06:07 AM
    It is highly improbable that a faulty main board will give you the superbright display on the monitor. The signals that come from the main board...
    32 replies | 464 view(s)
  • daver2's Avatar
    February 12th, 2017, 11:50 PM
    daver2 replied to a thread TU56 DECtapes in DEC
    Thanks for the offer Jack. As you say, let's see if anyone nearer to me chimes in first. If not I'll send you a PM in a week or two. Cheers, ...
    4 replies | 188 view(s)
  • daver2's Avatar
    February 12th, 2017, 06:12 AM
    daver2 started a thread TU56 DECtapes in DEC
    Does anyone know where I could beg, borrow, steal or buy a couple of 3/4" magnetic tapes for a TU56 DECtape unit I will be restoring during the...
    4 replies | 188 view(s)
  • daver2's Avatar
    February 12th, 2017, 04:00 AM
    daver2 replied to a thread Sick SuperPET in Commodore
    I would wait for the new ROM before proceeding. However, if you look at the four outputs from U36 (A, B, C and D) you can see what bank should...
    165 replies | 6223 view(s)
  • daver2's Avatar
    February 11th, 2017, 01:10 PM
    daver2 replied to a thread Sick SuperPET in Commodore
    A lucky guess :-)! Yes, you need to poke the decimal address equivalent of $EFFC with 0 for bank 0, 1 for bank 1, all the way up to bank 15. ...
    165 replies | 6223 view(s)
  • daver2's Avatar
    February 11th, 2017, 11:35 AM
    daver2 replied to a thread Sick SuperPET in Commodore
    No problem - here is my thought pattern: Each DRAM chip on the SuperPET is 64Kbits - so there is one device per data bit (unlike the 8032 main...
    165 replies | 6223 view(s)
  • daver2's Avatar
    February 11th, 2017, 02:28 AM
    daver2 replied to a thread Sick SuperPET in Commodore
    Interestingly, I can't see on the PET main board that R/W is gated with the ROM selection? Presumably you end up with bus contention if you try to...
    165 replies | 6223 view(s)
  • daver2's Avatar
    February 10th, 2017, 04:17 PM
    daver2 replied to a thread Sick SuperPET in Commodore
    Even with a 4K edit ROM fitted, the superpet should still boot in 6809 mode (as the /NOROM signal should be active when in 6809 mode - thus disabling...
    165 replies | 6223 view(s)
  • daver2's Avatar
    February 10th, 2017, 11:14 AM
    daver2 replied to a thread Sick SuperPET in Commodore
    MikeS, Yep. Sounds about right. One thing I also forgot is the 8032 ROMs are also disabled by the /NOROM signal when the 6809 CPU is active. I...
    165 replies | 6223 view(s)
  • daver2's Avatar
    February 10th, 2017, 08:07 AM
    daver2 replied to a thread Sick SuperPET in Commodore
    I think that program listing is the one that contains a bug... Yes, you are correct. For a Standard PET - the $9xxx area is reserved for optional...
    165 replies | 6223 view(s)
  • daver2's Avatar
    February 5th, 2017, 11:34 PM
    daver2 replied to a thread Sick SuperPET in Commodore
    One of the PET threads had a simple BASIC memory test, can't just find it at the moment. The earlier posts in the thread contained an error (as did...
    165 replies | 6223 view(s)
  • daver2's Avatar
    February 5th, 2017, 11:32 AM
    You are generally responsible for saving and restoring the state of the CPU not the compiler writer. If the compiler writer was to do it, he/she...
    2 replies | 119 view(s)
  • daver2's Avatar
    February 5th, 2017, 10:56 AM
    daver2 replied to a thread Sick SuperPET in Commodore
    You should also be able to see a 'new' block of RAM at $9xxx with the superpet board installed. The on-board 64K of superpet RAM is 'bank switched'...
    165 replies | 6223 view(s)
  • daver2's Avatar
    February 5th, 2017, 10:50 AM
    daver2 replied to a thread Sick SuperPET in Commodore
    Switching from 6502 to 6809 mode whilst the machine is ON is perfectly safe. What this switch does is to enable one processor and disable the other...
    165 replies | 6223 view(s)
  • daver2's Avatar
    February 4th, 2017, 02:15 PM
    daver2 replied to a thread Sick SuperPET in Commodore
    Thanks for reminding us that the superpet mode did work initially. This is a good indication that it isn't terminal! How do you try to get it to...
    165 replies | 6223 view(s)
  • daver2's Avatar
    January 31st, 2017, 01:52 PM
    daver2 replied to a thread Heath HT-11 OS in DEC
    No problem - we all have to help each other out with this 'hobby' as shops are hard to come by these days. Thanks (in return) for your link....
    107 replies | 5005 view(s)
  • daver2's Avatar
    January 30th, 2017, 12:19 PM
    daver2 replied to a thread Sick SuperPET in Commodore
    +1 for dave_m's post #97... Dave
    165 replies | 6223 view(s)
  • daver2's Avatar
    January 30th, 2017, 03:56 AM
    daver2 replied to a thread Heath HT-11 OS in DEC
    If you are running out of floppy disks you can still buy them from http://www.athana.com/html/diskette.html. Don't expect them to be cheap though......
    107 replies | 5005 view(s)
  • daver2's Avatar
    January 29th, 2017, 02:41 PM
    daver2 replied to a thread Sick SuperPET in Commodore
    Well done for getting the 'standard' PET going! Why not have a go at the 6809 board? If you get an image on the screen after you have selected...
    165 replies | 6223 view(s)
  • daver2's Avatar
    January 23rd, 2017, 01:00 PM
    daver2 replied to a thread Heath HT-11 OS in DEC
    I think you'll find that those odd MMI 20 pin devices are small address range, byte-wide bipolar ROMS and not PALS. If I am correct, there should be...
    107 replies | 5005 view(s)
  • daver2's Avatar
    January 22nd, 2017, 03:17 PM
    daver2 replied to a thread Heath HT-11 OS in DEC
    Thanks for the photographs. In a slightly later post I found out from the internet that the bootstrap ROMs should be on the disk controller starting...
    107 replies | 5005 view(s)
More Activity
About daver2

Basic Information

About daver2
Location:
UK - Worcester
Occupation:
SW/HW design engineer

Statistics


Total Posts
Total Posts
1,028
Posts Per Day
0.60
General Information
Last Activity
Today 02:32 PM
Join Date
June 19th, 2012
Referrals
0

1 Friend

  1. Zetopan Zetopan is offline

    Junior Member

    Zetopan
Showing Friends 1 to 1 of 1