Hey hey- new hackvisioner

[SG57]

So I ordered my hackvision kit few days ago, came today, got the components assembled and got it running in an hour. Hacked an old answering machine power cable for the 9v and chopped 2 RCA-to-miniusb cables, soldered them together to get the male-male rca cable. this is my first MC homebrew project and i pretty much hacked everything but the hackvision itself together, feel pretty good about that. Sadly, i’m a broke co-ed who’d rather order the $2 ttl break out board from china than the $20 usb-to-ttl cable from radio shack sooo i’m stuck waiting 2 weeks til i can reprogram this bad boy T.T

Onto my main point – I’ve worked on plenty homebrew software projects before, so I have an idea of how far i can push a 333mhz processor with 16mb ram. I am curious what the specs are for this little guy? 16mhz, 4kb ram? Sorry if it’s said somewhere and I missed it. Also, if i were to add a controller, how much current does it have to work with before it needs to draw it’s own power from a battery or whatnot?

thanks!

[Michael]

The ATmega328 microcontroller has 2K of SRAM and runs at 16MHz clock speed. The games for Hackvision push it to the absolute limit. There are literally only a few bytes of memory available after I programmed Space Invaders and Asteroids. I had to program very cleverly just to cram those games into the constrained environment.

As for current, the onboard voltage regulator can supply 100mA. I’m not sure what kind of controller you envision, so it’s hard to say if you would be drawing any current…

[trodoss]

@SG57,
Hi there!

As Michael said, the ATMega328 is has limited SRAM (2K) and processor speed (16 MHz).

I found that using PROGMEM for as much as possible is essential (see: http://www.arduino.cc/en/Reference/PROGMEM if you are not already familiar).

The TVOut library has some very nice features, however I have found that you have to extend at least a few to work well with bitmap graphics games. I am sure the same is true with vector-based games.

Due to how TVOut works, you have to use polling serial for debugging instead of the others that are normally used in the Arduino IDE (if you plan on debugging that way).

As far as adding a processor/co-processor I know that the Gameduino project already adds an FPGA as a graphics co-processor to an Arduino-based project, so it would work for a lot of ATMega chips.
http://excamera.com/sphinx/gameduino/

There are also other projects that add other chips (like the Parallax Propeller MCU) as a “graphics co-processor” for an Arduino/AVR (DigiStorm (not yet released), or Chameleon: http://www.xgamestation.com/view_product.php?id=51).

Technically, it would even be possible to add another AVR as a graphics co-processor, or use an R2R ladder, or another chip like the AD725
See: Uzebox – http://belogic.com/uzebox/index.asp

Any of those options can be “trumped” with a nice little color LCD with an SPI interface, and have the added benefit of portability. Something like this works well: http://adafruit.com/products/684 There are plenty of others available as well.

To me though, as interesting as these options may be, it comes down to a philosophical question: Do I want to get the most that I can out of a single chip (for the challenge), or do I want to add hardware/glue logic to make a simple chip do something “big” (ie: running Linux, http://dmitry.co/index.php?p=./04.Thoughts/07.%20Linux%20on%208bit). Either are fun, it is just a matter of what you want to do. I go down the path of using minimal hardware to make something interesting.

For a nice balance between minimal hardware/software and ease of programming on an AVR-based platform, Hackvision is a great product! Other alternatives will lead you down the path of more complexity (either in hardware or software) for really not a significant benefit. What do you need to have a good game platform? Video (in one form or another), sound, and a controller (or other user input). You have all of that on the Hackvision in one product.

[Edit:] Lol! That totally sounds like marketing copy, but seriously, I mean it 😉

Hopefully that helps.
–trodoss

[Author]

Posts