Image Map Image Map
Page 7 of 7 FirstFirst ... 34567
Results 61 to 70 of 70

Thread: Ruud's diagnostic ROM for IBM PC, XT and compatibles

  1. #61

    Default

    Quote Originally Posted by Trixter View Post
    In other words, don't worry if your diag rom doesn't work on drastically-different clones.
    I don't worry at all. I know it is more or less XT incompatible but what really really surprised me is that the test stopped at the third run. Still have to give the whole thing a good look but being human I have only one time line and in that time line not so much free time
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

  2. #62
    Join Date
    Feb 2010
    Location
    Russia, St.Petersburg
    Posts
    192

    Default

    Ruud Read a Private Mail please.

    I'm trying to repair a dead XT clone (taiwanese XL-7 motherboard). I've replaced dead 2x74LS245 and one 74LS273 (a latch on hi addresses between CPU and ISA slot).
    It starts your Test ROM but _hangs_ very early on the diagnostic Point 4. Seems it does something weird between Point 4 and Point 5 (Video initialization).
    My video is a CGA clone (RY-3301, it works on the another good XL-7 clone board with the same Diagnostic ROM).
    So motheroard can read end execute ROM and can output to diagnostic LED.

    I have no idea how it could hangs, there is linear video initialization code there.

  3. #63

    Default

    Sorry, I often forget to check the PM. Will do that this evening.
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

  4. #64

    Default

    Ruud,

    Thank you for the superb work. I was wondering can you add serial video output to your code? What I mean by this is in a system w/o working video or noncompatible video one would connect a terminal to the serial port and be able to see the output that would normalky go to the screen? Thank you.
    Current Wish List: 1. IBM 7531 Industrial Series PC 2. NEC MultiSync XL (JC-2001) Monitor 3. Copy II PC Enhanced Option Board (the one with the toggle switch on the back) 4. MicroSolutions MatchPoint AND/OR UniDOS card 5. Compaq 14" VGA CRT Monitor (the one that came with the SystemPro). If you have any of the above for sale please PM me. Thank you!

  5. #65

    Default

    Quote Originally Posted by alecv View Post
    Ruud Read a Private Mail please.
    - please name a source file with name containing version i.e. diagrom-2019-03-05.zip I already have at least two 'diagrom.zip' files...
    In this way you can see there is a new version. OK, I'll do that.

    - There is no Version: header on the screen
    I don't now when I added that but there is one now.

    - CGA has only 16Kb of memory. I saw in comments: you are considering CGA has 32K. It's wrong.
    Indeed that is wrong. But I only test the screen memory so no harm is done.

    - DIP Switch on this XT displayed incorrectly. This XT clone has very generic schematic of the 8255 PIO.
    I cannot check it now. In the past I used an Unitron board that did not have the standard dip switch settings. In the mean time I located some some Taiwanese clones. I will use one of them ASAP to test the DiagROM.

    - I'm testing mb w/o keyboard and FDD. It hangs too long trying to read from non-existent floppy controller. (BIOS just reported about FDC absesnse)
    I saw in your movie what you meant. I'll change the ROM so it won't try to read the floppy when the FDC test fails.

    - After test it restarts too quickly! I can't read right half of screen.
    Your movie shows that the screen is completely cleared and that is not supposed to happen at all. Could it be possible you are running a very old, may be even the first version? That was just to show what the idea was and a lot of things weren't working correctly.

    - Test pass count not incremented
    That should work. So I again think you are running the first version.

    I found two bugs in the mean time:
    - I forgot to remove some comment that disabled a loop. This loop is needed to test the refresh. But when it is present, the checking of the RAM takes "ages". So be prepared that the new ROM will be quite a bit slower, Sorry.
    - I only tested the ROM with a MDA card. I just tested the ROM with the PCem emulator and saw that in CGA mode the dip switches aren't displayed at all. Weird, I'm sure it did so in the past. So back to the drawing board. (displaying something incorrectly is something else than not at all, IMHO)

    I'll notify you all when I have a new version. Please give some days, I have a privat life and family as well.
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

  6. #66

    Default

    Quote Originally Posted by Shadow Lord View Post
    Thank you for the superb work.
    Thank you very much!

    I was wondering can you add serial video output to your code?
    No, and I have three reasons for it:
    - I'm not creating things just to please others. I created this ROM because I had a need for it and the Landmark ROM was not good enough IMHO. Your request is not in my interest and having not that much free time, I have to say no. But I hope to retire in about seven years. If you still need this feature, please ask me
    - I output codes to various I/O ports, including LPT1. The outputted code should show you what the ROM is doing or where it stopped.
    - You probably noticed the various counters. They are not stored in RAM because that is cleared and tested every time. Landmark kept track of the counters by reading and upgrading the numbers on the screen. I partly stole this idea: I use the video memory outside the actual screen memory. That means I have 96 bytes for storing the counters. When using the serial output, I think I can forget about the counters.

    On the bright side: the sources are free so feel free to add this feature yourself. I don't mind helping you in some way if needed.
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

  7. #67
    Join Date
    Feb 2010
    Location
    Russia, St.Petersburg
    Posts
    192

    Default

    Ruud thank you for support.

    Unfotunately my XT-clone motherboard is faulty. It hangs forever when I/O card trying to use IOCHRDY ISA signal.
    My CGA card has slow DRAM so it uses IOCHRDY. Hence it hangs trying to clear video memory (between codepoints 4 and 5).
    ADDRESS=B000h, DATA=20h, MEMW=Active

    Motherboard does not hangs w/o CGA card. This CGA card works OK in the similar motherboard.
    It's hardware fault. not a Test BIOS fault.

    Schematic:
    http://ixbt.photo/?id=photo:874739
    seems DD44, DD32

  8. #68

    Default

    Quote Originally Posted by alecv View Post
    RuudIt hangs forever when I/O card trying to use IOCHRDY ISA signal. My CGA card has slow DRAM so it uses IOCHRDY. Hence it hangs trying to clear video memory (between codepoints 4 and 5).
    ...
    Motherboard does not hangs w/o CGA card.
    If a card sets IOCHRDY, the same card should also release it. In 1986 a friend and I built a card to measure EEG signals with a PC and we needed a delay. We used a 74LS393 counter that set IOCHRDY and released it after 8 clock cycles. For one or another reason your CGA card does not release IOCHRDY.

    This CGA card works OK in the similar motherboard.
    IMHO "similar" does not mean "the same". But it still sounds quite weird.

    Schematic:
    Unfortunately the image is too dense. Not understanding Russian and not having my wife at hand right now, I don't know if there is a link to download a better picture. And I also have no idea what you mean with DD44 and DD32 (ID of ICs, coordinates?).

    I can advise you to use another (type of) video card but I think you would have if you had one.
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

  9. #69
    Join Date
    Feb 2010
    Location
    Russia, St.Petersburg
    Posts
    192

    Default

    Ruud Don't bother! I'm just telling it's not a (your) software problem!

    Both my motherboards (semi-dead and working) are XL-7 Turbo, rather popular (and clonable ) Taiwanese Turbo XT.
    Later Bulgarian Pravetz computer plant also have been producing this motherboard clone too.
    Hence this board was popular in post-USSR Russia till early 1990-th.
    You can find Hi-resolution schematic link below the image (see a 4704 x 3055 digits)
    This schematic 99.5% matches original XL-7 Turbo and may be considered as clone-of-clone...
    DD44 is a U44, a IC number.
    Sorry for russian IC types we have to live in "bilingual" electronic environment here.
    i.e. K555LA3 == 74LS00

    Anyway, this hardware problem is not detectable by any sort of BIOS...

  10. #70

    Default

    Quote Originally Posted by alecv View Post
    Ruud Don't bother! I'm just telling it's not a (your) software problem!
    I'm sorry if I raised that suspicion but I already understood that.
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •