Hi
In my quest to learn more about the tile structure in Pac-Land I needed to write a tile viewer application that could display all the tiles in the two tiles eproms (foreground tiles and background tiles). I was thinking about writing a Windows or OS X app to do this but then I thought "why not write an app that runs on the Pac-Land hardware itself?" It made perfect sense! The Pac-Land hardware can display its own tiles right out of the box so why go to all the trouble of re-inventing the wheel when all you've got to do is write a bit of 6809 code! ;-)
So here we are!
Pretty neat huh!
I know enough from my disassembly work on the game to bring the hardware up safely now from a cold boot. The bring up process isn't too hard, you just need to communicate with the sub-cpu to make sure it's woken up and checked itself out safely. Once you're happy that the sub is up and running then you've got full control of the hardware.
The reversing of the palettes/seasons/lookup tables took a bit of figuring out but I got there in the end. The Mame source helped.
This app runs on all versions of Pac-Land in Mame by replacing the rom at 8D with my supplied binary. I've also obviously tried it on my real board and it works fine on that too.
This probably wont be of much interest to many people but it helped me in understanding the tile/palette/season format and opened the doors for fun in the future....
I'm providing the full source for the app, as well as the assembled binary.
Have fun!
https://www.ukvac.com/forum/data/uploads/1497/tileviewer.zip
In my quest to learn more about the tile structure in Pac-Land I needed to write a tile viewer application that could display all the tiles in the two tiles eproms (foreground tiles and background tiles). I was thinking about writing a Windows or OS X app to do this but then I thought "why not write an app that runs on the Pac-Land hardware itself?" It made perfect sense! The Pac-Land hardware can display its own tiles right out of the box so why go to all the trouble of re-inventing the wheel when all you've got to do is write a bit of 6809 code! ;-)
So here we are!
Pretty neat huh!
I know enough from my disassembly work on the game to bring the hardware up safely now from a cold boot. The bring up process isn't too hard, you just need to communicate with the sub-cpu to make sure it's woken up and checked itself out safely. Once you're happy that the sub is up and running then you've got full control of the hardware.
The reversing of the palettes/seasons/lookup tables took a bit of figuring out but I got there in the end. The Mame source helped.
This app runs on all versions of Pac-Land in Mame by replacing the rom at 8D with my supplied binary. I've also obviously tried it on my real board and it works fine on that too.
This probably wont be of much interest to many people but it helped me in understanding the tile/palette/season format and opened the doors for fun in the future....
I'm providing the full source for the app, as well as the assembled binary.
Have fun!
https://www.ukvac.com/forum/data/uploads/1497/tileviewer.zip
