Jump to content

dhe

+AtariAge Subscriber
  • Posts

    1,841
  • Joined

  • Last visited

Posts posted by dhe

  1. This Sunday's event was very enlightening. Much discussion about TI's unreleased products, and even some cards that weren't meant to be products.

    Other discussions where on MICE in the TI world, it started with the Mechatronics mouse that @arcadeshopper managed to wear out from use!

    Later Mike Maksimik released the Asgard Mouse (serial) and Myarc released a mouse (using the 9938) to go with MyArt.

    Mike also created MIDIMaster to hook up synthesizers.

     

    This led to talk of early sound cards (PC) being sold to gamers for not only sound, but to hook up things like joysticks. Related to that, I've been reading up on the Atari ST line, which includes MIDI built in. In addition to it's original purpose, people used them to create small networks for co-op games. They were also used by Sierra in games like Kings Quest. So, if it found a MT-32 hooked to the system, at certain parts / events you MT-32 would start playing music.

     

    We have MIDIMaster, now all we need is a game to take advantage of it! 😃 We also have the SID-Blaster that I don't think any game is taking advantage of.

     

    These ramblings are kind of a new thing, if any part makes someone anxious, please PM me and I'll work out a fix.

    • Like 6
  2. 23 hours ago, Duewester said:

    Now I just have to beat my wife to the mail and pay off the credit card before she finds out how expensive this has been.

    Yea... I know that feel. But, I had to spend a $1000 dollars in tools and parts, to fix the $25 console I bought at a garage sell!

    • Like 3
  3. Since this topic has drifted a bit anyway. GPL - did TI write any of it's arcade games in GPL? The source code for Invaders and Parsec and Tomb Stone City are all in assembly. And sometimes the GROM's just held assembly or basic code, like good little storage devices. Back in the early day's of owning a 4a, I always equated a GROM with GPL code.

    • Like 3
  4. Amazon has a free sample of the book:

      Racing the Beam: The Atari Video Computer System (Platform Studies)

     

    The free sample is a really interesting study of the early early days of video gaming starting in labs (think o'scope display), moving in to bars and pizza joints and finally in to the living rooms, with a side of the origins of different types of well established game types of today (adventure, FPS, etc).

    • Like 3
  5.  

    On suggestion, I went over to JS99er and was running the F18A demo's collected there.

     

    One was a very well represented screen of Super Mario Brothers. I remember at one time, there was an add for a Mario Brother like game in Micropendium.

     

    Does anyone have a copy of that, I'm interested in how close that came to the original.

     

     

  6. mame -debug -bios 1.00

     

    You can add -debug that might help give you some clues, also, you can call out the bios version you want to use.

     

    I would compare what boot files you have, compared to what BIO's you are using to boot with, Beery made some changes on BIO's V2.

     

    The is an option built in to TI Image Tool to install a new MDOS in to an HD image, that might need updating to work....

  7.  

    Here is your chance to call the baby ugly!

     

    My main annoyances:

     

    Using a DB9 for both the joystick and cassette port.

     

    Almost no CPU RAM on bare console.

     

    Writing an interpreted language in GPL.

      Even the VIC and Sinclair people got to kick sand in my face, because you did for i=1 to 100 in ten minutes.

     

    32K Interface - on an 8-bit bus with wait states.


    No headphone jack.

     

    Digital, not analog joystick interface.

     

    DMA lines not brought to the pbox.

     

    Soldering all the interrupt levels together.

     

    The transformer stays on, even when the unit is off.


    Hard to use on/off switch.

     

    Fctn-= to easy to reset basic.

     

    Out of the box, no way to load machine code - not that there was a place to load it.

     

    6K GROMS - why 6? Why not 8K or 1 or 2?

     

    A memory map that looks like someone just started listing things that need a 'block'.

     

    A 90 degree GROM Port

     

    • Like 3
  8. I appreciate everyone's feedback, the core take away's for me:

    1) no hold pin, no DMA transfers.

    2) the reference to DMA in the MyARC HFDC manual is 'private' DMA on the board.

    3) the wikipedia article is not perfect. 😃

     

    Another design decision that made the 4a poorer than it needed to be.

     

    One day, when I'm smarter, I need to revisit the Culp code to do data transfers to CPU memory, avoiding the double transfer from VDP buffers to CPU RAM. While this has nothing to do with DMA, if it works, it eliminates one step that doesn't add any value.

     

     

    • Like 4

  9. I'm trying to understand DMA in the 4A world.

     

    I found this on wikipedia:
    The processor can be paused with the address bus tri-stated for external direct memory access (DMA). Memory accesses are always 16 bits wide, with the CPU automatically performing read-before-write operations for byte-wide accesses.

     

    The only card I know that claims to do DMA is the MyARC HFDC.

     

    It's documented in the manual here:
    CRU OFFSET RELATIVE ADDRESS    DEFINITION           ACTIVE
              >02             >04                 DMA in Progress      High

     

    Do you get DMA for free on all reads and writes, or do you have to set it up in assembly?

     

    Does it really buy you any real world performance as implemented on the HFDC?

     

    People looking at the MyARC FDCC said it looks like a second iteration would have been setup for DMA....

×
×
  • Create New...