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danwinslow

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Posts posted by danwinslow

  1. Posted

    Ok, could someone explain to me why an 8 bit couldn't be overclocked in an even multiple of its speed now? My dim understanding is that the 1.79 mhz rate was chosen to sync with the tv signal and vblank, etc. But tv issues aside, are there technical reasons we could not run the whole atari at say twice that speed?

  2. Posted · Edited by danwinslow

    Ok, thanks to you guys, got this worked out. The correct response is not a NAK or an error, but nothing at all. Me NAKing the type 3 poll was confusing the poor thing. If no response at all is received it times out quickly, although it does cycle through 20 or so type 3 and type 4 polls, but if not responded to they go quickly, so the delay all in all is just the standard extra bit of time for an XL boot and the contented farting noise.

     

    Most of this you guys had already told me, but yknow.

     

    Thanks!

  4. Posted

    Thanks, Bryan. There doesn't seem to be much information on how to respond negatively; I mean, I have no handler to upload. The 130xe seems to hang around waiting for something on its type 3 poll; it takes quite a while, and does get evenatually past it after doing 2 type 3's and 2 type 4's. I expected to be able to nak it or error it and it would give up but it doesn't seem to pay attention to the naks/errors.

  7. Posted · Edited by danwinslow

    I am writing a small program to allow an 8 bit to boot off of a single board computer. The initial boot load seems to go ok, but at the end of that sequence I get some commands with a device of $4F and a command of $40. Here is a (commented) log snip of the sequence at the end :

     

    processing header 31 52 4f 0 d2 //this is the regular boot sequence running

    // a 'read sector' for d1: sector 4F

    send data frame, 128 bytes checksum fc

    MSR 0

    processing header 31 52 50 0 d3 // next sector...etc.

    send data frame, 128 bytes checksum 49

    MSR 30

    processing header 31 52 51 0 d4

    send data frame, 128 bytes checksum 1d

    MSR 0

    processing header 31 52 52 0 d5

    send data frame, 128 bytes checksum 2a

    MSR 0

    processing header 31 52 69 1 ed

    send data frame, 128 bytes checksum 8d

    MSR 30

    processing header 31 52 6a 1 ee

    send data frame, 128 bytes checksum 0 // boot sequence over now

    MSR 30

    processing header 4f 40 4f 4f 2e // and I get this ?

    unhandled device code : 0x4f

    MSR 30

    processing header 4f 40 4f 4f 2e

    unhandled device code : 0x4f

    MSR 30

    processing header 4f 40 4f 4f 2e

    unhandled device code : 0x4f

    MSR 30

    processing header 4f 40 4f 4f 2e

    unhandled device code : 0x4f

    MSR 30

    processing header 4f 40 4f 4f 2e

    unhandled device code : 0x4f

    MSR 30

    processing header 4f 40 4f 4f 2e

    unhandled device code : 0x4f

     

     

    So does anyone have any idea what the command of ' 4f 40 4f 4f 2e' is? I can't find a device or command that matches those numbers.

  12. Posted

    Old, unused ideas that seem good are old and unused for a reason. Basically your idea is on the right track, but its certainly something that very few if any hobbyists would have the skill or fabrication technology to accomplish. And anyway, its been done already in the form of faster processors.

  13. Posted

    Trigun is an almost perfectly clue-free source of information about programming the 2600. You do indeed need assembler, and *hard* assembler at that, plus a detailed and in depth knowledge of the hardware in order to even begin programming the 2600.

    You could, however, learn to program on a more modern computer in Basic, and then move on to assembler, and then onto the 2600.

  15. Posted

    I'd rather see some multitasking programs in which the individual programs are fully featured and graphical.

     

    Well, so would all of us, but thats a tall order on an 8 bit atari. Maybe you shoudl go write one for an IBM PC with 1GB memory and a p4 processor. Oh wait, its been done. :)

  16. Posted

    Ouch! Thats sucks. Not to be a pain, but the *real* lesson here is that we should all be backing up any development data we have on a regular basis. I had this happen to me on an atari ST about 10 years ago when I was writing Hero III, and since then I go out of my way to back up my stuff.

  17. Posted · Edited by danwinslow

    I *have* looked at contiki. It's very cool. If I get my ethernet thingy working I am going to mod contiki to use it.

     

    As far as multitasking goes, they are probably correct that something like a full fledged MT OS is impractical. However, a very thin, non-preemptive task switching system is practical. There would be a main thread, and then background service threads ( possibly interrupt driven ), but no large amount of tasks, memory protection or virtual memory as such.

  19. Posted

    Well. It was sometime back in the (very) early eighties...I was a young geek in the strange land of Nebraska. I had joined the Air Force in a sudden fit of wanderlust and they had nabbed me immediately, ran me through boot camp, and then mailed me to Offutt AFB, Nebraska. I loved two things : Atari and a young lady. I married the lady, but eventually I moved on from the 2600 to the actual computers...but I kept the 2600 around. Every now and then I would drag it back out and play again for a while. I especially loved Adventure...what a cool, cool game, even if the dragons looked like spastic ducks. I played it for hours.

    After we had been married for about 2 years, we got an assignment to Germany. We packed up all our stuff, and when it came to my 2600, for some reason we decided to take it along as we went around the country seeing relatives before the long tour overseas.

    When we were at my wifes parents house, I got slightly bored and hooked up the 2600. My wife's mother was a very sweet little old lady type...think tiny librarian with REALLY thick glasses, so thick that it gave her a kind of goggle-eyed appearance. She was very quiet and generally just sat around and talked softly and giggled occasionally when something amusing happened. I heard later that she could be a bitch on wheels when drunk, but she had stopped drinking for good in her 20's. Anyways, she saw me setting up the 2600, and she came over to watch. She seemed really interested, so I puffed up and gave her a long speech about everyhting, and then started playing Frogger. She sat and watched me for about an hour. I figured she must be pretty bored.

    When I quit, I asked her if she would like to play. She laughed and said she could never, but I showed her the joystick and how to hold it and walked her through messing around with Frogger. I watched her play for a while, and she seemed to have a really good time.

    The next day we started playing Adventure, and she was FASCINATED. She seemed to like it so much that I just decided we would leave all that atari stuff with her. She seemed pleased and we went off to Germany.

    Well, eventually she passed away. When we went back to the funeral, we had long conversations with people about her and they would always mention how much she loved the atari and especially 'that game with the duck things'. She would play it for hours and hours, and she beat every variation the game had to offer, and found the secret room or whatever it is...something about a moveable bridge..I forget. But I like to remember how much she liked it and how the simple machine we love could bring fun to someone from a different age completely.

  22. Posted

    Well, I've been looking at it, and it seems to be driven off of one of the NMI interrupts, and he is doing full page stack copies on context switch. There are 2 tasks set up. The basic idea for multitasking is to preserve the stack and all of the CPU registers for each task, and then copy them down for a context switch. In practice page zero locations, at least some of them, need to be preserved as well, due to the fact that page 0 is used as virtual registers a lot.

  23. Posted

    I am trying to find a VGA monitor that can be used with my Mega STE. I have a special cable from best electronics that converts the 13 pin DIN from the Mega to VGA. That seems to work fine for mono output, but the color output horizontal scan rate is around 15khz, which is out of range for all of my monitors. So...I am looking for a currently produced monitor that has a horizontal frequency low of 15khz...or some suggestions as to how to locate a used monitor that has that HF scan rate ( besides ebay )..*OR* an answer to this question :

     

    I know about VGA upscan converters...I know these take composite/RGB and upscan it to standard VGA...but can they be used to 'upscan' the horizontal frequency? The one I have has a VGA input, but I kind of thought maybe that was just a passthrough, but now I am wondering if it could double the horizontal frequency scan rate on the way through.

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