At Brad's invitation, here is a preliminary wiring diagram and a picture of the prototype for my single chip 8x8 game based in part on his old "Great Race" project. The low parts count design will support both CCR (common cathode row) and CAR (common anode row) type red/green displays by changing the polarity of diodes D1 and D2 and by configuring R1 to be either a 'pull-up' or a 'pull-down'. I would be happy to post software at a later time if anyone is interested. Right now I'm having way too much fun coding game variations and tweaking program performance (lol).

Happy Holidays and cheerful regards, Mike

I could have sworn that i replied to this post yesterday but must not have...

Thanks very much for sharing and i think its great that you can quite easily make it work with various display configurations. I would love to add it to the great race page if you wouldnt mind?

You're welcome to post this design on your Great Race page, Brad. I've added an example wiring diagram for the "common anode row" type display below with pin numbers for the little 1.25"x1.25" Sure LE-MM103 display, which I believe is similar to the one you used on your original Great Race project. Compared to the diagram for the other type display, notice that the pull-down resistor R1 is missing in this diagram and the polarity of diodes D1 and D2 is reversed. Please note that the software is slightly different for each type of display too.

If you can give me a few days, I will clean up and post a version of your original Great Race program that will run on this new hardware. Software for the "Motocross" game will also take awhile longer.

Would you mind if I posted this project on Digital-DIY and/or another Forum/Project site, with credit to you as originator of the concept and links back to your web site and your Great Race project page? I realize you've moved on to bigger and better things but I suspect there are still a lot of people who might enjoy building this little project.

Cheerful regards, Mike

Hi again Mike and apologies for the late reply - we have had a busy Christmas!

I would be more than happy for you to upload your design to whatever sites you would like - especially digital-diy (those guys have helped me alot with swordfish basic and visual basic!)

There's no rush in getting around to it, hopefully things will settle down a little bit for me and i'll get a chance to get it uploaded when ever you are ready.

and by the way, I love revisiting old projects and making them better

Thank you, Brad.

I've attached the source file for a version of your Great Race program written specifically for the single chip (16F1828) board with a CCR (common cathode row) type display. Fear not... it's relatively easy to modify the program if you have a CAR (common anode row) type display like the Sure LE-MM103. To change the display type in the program, simply comment out all of the lines with '(CCRow)' text at the end of the line in the source file, then un-comment the lines with '(CARow)' text at the end of the line, then build a new hex file. Note that the source file uses "absolute" mode.

Besides program changes for directly driving the display without a 7442 IC, there are only a couple changes from the original program worth mentioning;

(1) The program starts up in a "scrolling message display" mode. Press <left> switch to start the game.
(2) A 16-bit table pointer allows using tables larger than 256 bytes (larger messages or more track data).
(3) The display is refreshed one dot at a time instead of one row at a time to even out the brightness.
(4) Program structure was changed to eliminate stack overrun errors that occur in the original program.

If I have time I will try to go back and use conditional assembly directives to make it easier to generate hex files for either CCR or CAR type displays. I don't really have a way to test code for common anode row type displays (anyone willing to send me one of their spare LE-MM103 displays?).

Have fun. Cheerful regards, Mike

Many thanks Mike and apologies for the late response here. Have been quite busy trying to finalise the PICnDuino.

I will see about getting this upload sometime this year

once again. I especially love it when someone improves upon and modifies old projects. I guess thats why we have sites like this and digital-diy.