Yikes - more than 2 years without blogging!

Not the kind of anniversary I wanted to celebrate. Anyways, I'm in the middle of a move to a new house, and work is heating up. So, hopefully around October, things will settle down...and I will try to post something more regularly.

The Road to Reality

I have been interesting in Physics as a hobby for a very long time. Back in the mid-90's, I was reading about Quantum Mechanics and Relativity on a fairly regular basis. I had to really dig to find books that were deeper than a purely "popular" treatment, but not so deep that an engineer could actually make sense of them. Some math, not all math.

Having been trained as an engineer is "almost enough" to handle "some" of the math, but I ended up with an awfully long road ahead. I eventually got a bit discouraged, but never quite gave up. (Emulation came along and I got a bit distracted for a number of years.)

In 2004 Roger Penrose wrote a giant book on Math and Physics, call "The Road to Reality: A Complete Guide to the Universe". It is a highly mathematical, modern treatment, but it builds on itself such that, theoretically, someone with some math background can actually understand it all. (At least, they'll be able to self-direct to other resources as needed.) There are 16 chapters of Math (the first 1/3 or so), followed by as many on Physics. For comparison, my formal math training ended at chapter 7. I now find myself in chapter 15, nearly finished with the math section. It is definitely not for everyone, but it's exactly what I needed.

Finally, I have found that discussing the details of the book can help a lot with the understanding. I recently created a Yahoo Group called RTRFANS, for just this purpose. With this book, and with internet resources that weren't available in the mid-90's, I've now got a shot at understanding truly modern physics.

Some porting work

I really need to post more often!

For a while now, I've been wanting to experiment with new methods of high-speed circuit simulation. The idea would be to prototype some discrete-audio stuff, possibly for MAME, using something like Python.

After looking into the requirements, I realized that I needed to handle polynomials with a single variable, and ratios of these polynomials. Also, I needed to be able to handle real or complex variables. I looked around on the web, and I found that SciPy is finally coming along nicely on Windows. However, I wasn't entirely happy with the root finder they use.

Along the way, I also found the ratfun package, which looked perfect, but was unsupported on Windows. I dug in and in a couple weekends, got it building under Windows. I think I'll be using it for the experiments, whenever I get back to it.

The Joy of LaTeX

Ok, I'm a geek. Over the past 10 years or so, I've worked on a handful of math and engineering problems that I thought were interesting. Yes, most of them were "spare-time" activities, although a few were inspired by work stuff. I recently made a list of all of them, and I suddenly had the urge to publish them. Maybe some other people will find these things interesting as well.

At any rate, I wanted a way to publish them with all the math equations, as well as generate PDF's and HTML. I had heard about LaTeX for a long time, but now I had a fine excuse to give it a try.

I first tried the TeXLive distribution, but I never could get it to work on Windows. (Maybe this has been fixed since then) Then I tried MikTeX. It was a fairly straightforward installation. After working out a few examples, I was hooked. My first draft of a test article turned out pretty well:

http://www.avoidspikes.com/textest/gamma.html

I use pdflatex to generate pdfs and htlatex (part of tex4ht) to create html + pngs.

At any rate, it's nice to see that free software can be used to do professional typesetting. I'm planning to use this stuff to document my math problems, as well as some theory behind discrete sound filtering in MAME.

Actual MAME-related work!

For those who haven't heard, the speech chip used in Berzerk has been reverse-engineered by "Lord Nightmare"! This is something I've been waiting for for about 7-8 years! I'm sure that the emulation will end up in MAME and PinMAME sooner or later.

Because of this, I spent some time over Christmas looking at the analog filters on the Berzerk speech board. (These are applied to the sound after it comes out of the chip.) I finished the analysis, and it should be pretty straightforward to add them into MAME after the chip emulation is done.

For what it's worth, I've been trying out Maxima with wxMaxima to do the symbolic math for circuit analysis. I know, I could have used SPICE or something - but doing the math from scratch makes it easier to understand what is going on.

After I worked out about half of the math for these filters by hand, I ended up with about 6 pages of algebra. At this point, I figured I should use this as an excuse for learning Maxima. Sure enough, I found an error on page 5. Darned minus signs! :)

The second half of the analysis took about 5 minutes, since the code from the first half was already done, and I could re-use it!

For those who care - the filter is a third-order lowpass - a first order lowpass, followed by a second order with a resonant peak around 2400 Hz.

Firefly and Serenity

Well, I did it. I managed to watch all the Firefly episodes before checking out the movie, with two hours to spare :)

I've got to say, with every episode I watched, I enjoyed the series more. The writing and character development is really well done, and it's pretty darned funny to boot. I can't believe they canceled it just as it was taking off. It was kind of the opposite of what Star Trek and Star Wars have been of late. Less tech, and much more fun. And this is from a guy who has a penchant for hard science fiction.

At any rate, I also enjoyed the film. I went with three others who hadn't seen Firefly, and they seemed to like it as well. I think it's quite a tough job to introduce this world and so many characters to an audience who may never have seen the series. Still the movie seems to do all this and more, with entertainment value that is missing in many other sci-fi films of late.

However, I actually think this whole concept works better as a TV series, rather than a series of movies. So, now I join the ranks who are hoping someone will bring back the TV show in some incarnation.

More non-emulation news :)

I have still been up to my neck in "real work". I hope it will slowdown in the next month or so. When I do get a few minutes - I am trying to read, and maybe catch up on TV a little.

I'm carving out enough time to finish Neal Stephenson's "Baroque Cycle." I find these books to be amazing. Exciting, intellectually challenging, but very rewarding. I feel like I've actually visited the late 17th and early 18th century. And Neal's themes about science, technology, commerce, etc. are quite intriguing.

As I side note, I TiVo'd the whole "Firefly" series, which I'd like to watch before I go see "Serenity". I haven't heard anything but good things about the movie.

I'm still here...!

Ok, I haven't done much on MAME at all, except that I bought a Zero Hour board on eBay. Hopefully I can improve the driver when I finally get time to work on MAME again, now that I'm intimately familiar with the starfield generator circuit. :)

I've been extremely busy with work and home life. One weekend, I built a giant play system for my kids. A lot of work, but it turned out pretty nice!

Finally, for those who visit my horribly outdated web pages at dsplib.com, - I'm giving up the domain. You can still reach those pages here, until I move them again. Pay no attention to the inactive blog pages there :)

MAME Quickies

I've submitted 2 updates to MAME in the last 3 days. The first is the much improved Space Raider. The second one hooked up the starfield generator code to Zero Hour and Red Clash. I'm still planning to write up something bigger on this - describing how it all works - but I've been too busy this week.

Space Raider Stars - done

Just a quick note to say that I've got the graphics on Space Raider 100% correct, including the starfield behavior. I've still got a couple things to look at, but my plan is to submit a driver update tommorrow. I'll try to add some screenshots a that time as well.

Speed Coin

I've had almost no time to finish Space Raider lately, so I thought I'd talk about the history of a game I own - Speed Coin.



As far as I know, I'm the only one with a Speed Coin cabinet. It's definitely a prototype, as the cabinet is made of nice plywood and not particle board. Also, the marquee and control panel are made of colored paper, colored electrical tape, and a blown-up xerox copy of a coin face. My understanding is that it came from Stern when it shut down.

The boardset is a Scramble, with hand-labelled ROM chips inside. Also, the wiring harness is different, since it only requires a 2-way joystick.

When I went to plug this into the Scramble driver in MAME (back in 1999!), I was stymied by the fact that the background was blue in MAME, but black on the "real thing". I traced through the PCB only to find that the monitor was adjusted with the blue gun turned off! When I adjusted it, it matched MAME exactly.

In case you are wondering about the sound, the music sounds kind of muted and noisy on the real thing, just like in MAME.

Last year, I was stunned to play Speed Coin in an arcade in Nashville, Tennessee. It turns out the Ultracade guys added that game to their Multigame system, under "Arcade Classics"?!. I'm sure they used the ROM images I dumped in my basement, and here it was on a machine in another city. Pretty strange feeling.

I really don't think it's a classic. More like "Arcade Relics". :)

Oh well, I'll get back to Space Raider this weekend, hopefully. I have a newly-found JAMMA harness and a brand new RGB-to-TV adapter which should make things easier. With that, I'll be able to take screenshots from actual boards, and compare them with MAME.