Path: utzoo!attcan!uunet!know!zaphod.mps.ohio-state.edu!ncar!umigw!mthvax!dnelson From: dnelson@mthvax.cs.miami.edu (Dru Nelson) Newsgroups: comp.sys.apple2 Subject: Re: Proposal: Apple II+ 60Hz Timing Signal Message-ID: <1990Nov2.155413.5794@mthvax.cs.miami.edu> Date: 2 Nov 90 15:54:13 GMT References: <5398@crash.cts.com> Distribution: na Organization: University of Miami Department of Mathematics & Computer Science Lines: 70 In <5398@crash.cts.com> mdavis@pro-sol.cts.com (Morgan Davis) writes: >Dru Nelson writes: >} Well, it is a good idea, but there is no need for it. Most ][+ users >} have upgraded. This would have been a great hack in 1981 or 80. >} There would have been a great opportunity to set a standard. >No, there is a need for it. I wouldn't have spent as much time hunting down >a solution if I hadn't been asked to make my software compatible with the II+. >You can't say, "there is no need for it" if my customers tell me that they >need it. Plus, in 1980 there were no other Apple II machines, let alone speed >up cards and processors which would affect hard-coded timing loops. Back then >it would have been a useless hack for the most part. Today, it is very >necessary if you writing any time-dependent code that you need to support >on the II+. In 1980, it would make animation flicker free and the interupts would make a nice little clock. Could you use the clock routines from ProDOS? >} Now, well, I would be interested in seeing how much support is there >} for such a thing. >I don't see why you'd care. It isn't a "let's vote to support it" to see >whether or not it is "interesting" to you. It is a problem that many >developers have recently come to terms with. Because unlike the IIe and IIGS >there is no pollable signal in the II+ that allows you to synchronize timing >in the same easy manner that you can on it's predecessors. Luckily, I keep an asbestos suit around :-) First of all, I sent you this in mail because I am not interested in bogging down the net with my statements of interests. I said it because I was curious about how much people were interested in such a thing. A lot of people are posting that it is a good idea, so there is interest. It was sort of saying that it would be nice to see what support is there. I understand the ][+'s signal/timing limitations. Have you tried reading the floating bus for timing? >} The VBL indicator is already there (as you probably already know). >Of course I know! How else would I have been able to write up my proposal >if I hadn't known? The problem with the II+ is that even though it has >a 60Hz signal that lives in the machine, it isn't mapped to a readable >register that software can use. On the IIe and IIGS, VBL can be detected >by reading $C019. Not so on the Apple II+. I know this also, but you didn't mention the other machines so I wasn't sure that you knew. However, I knew who you are and I added the "probably". >} p.s. Out of curiousity, would you know the address for any of the >} A+ or incider writers? >No. If I did I wouldn't let anyone else know without asking them first. That is understandable, however, I was just asking because some post their net address. Joe Abarnathy did an article on the internet and he posted his address. I will look it up when I see my friend, but I asked you because you are known to be involved with telecommunications a little bit :-) p.s. I have an Apple ][+. -- %% Dru Nelson %% Miami, FL %% Internet: dnelson@mthvax.cs.miami.edu %%