MarkeyJester, on 04 December 2016 - 12:20 PM, said:
That hardware looks beautiful!!
As a fellow 68k and Mega Drive programmer, the one thing I'm not too comfortable with, is the fact that the vector table and the registers need to be setup in a certain way to operate the debugger. Now, regarding the register setup, once the initialisation is done, are the registers now 100% free? ...or are a few of the registers (say address registers) needed throughout the game to allow the debugger to function? I wrote a game for the Mega Drive (with some Mega CD support) called the Chaos Layer some years ago, but, I needed every register I could get my hands on to keep it as optimal as possible, especially with some of the effects I was planning to do. If I were to obtain this, would setting up the debugger for my game require a lot of rewriting of code?
One more question, does this include (or do you intend to include) a debugger for the Z80 sub-CPU in the Mega Drive itself?
Either way, this looks incredibly useful, and what I do appreciate is the fact that you have a proper hard case shell, to accommodate the new components inside. It doesn't look like some dev-kit made in someone's garage, it looks like a solid piece of equipement, cool stuffs~
All the registers are free for use once the devkit setup is done. The only meaningful change is to inject the address of the SNASM handler into the TRACE interrupt, the rest are just niceties (passing control of all exception handlers to the debugger, etc). I can't speak for the MegaCD side though, I don't have it fully working yet, but I would assume it would be designed not to restrict the coders.
There is Z80 debugging functionality but I don't have the license for the Z80 debugger (the little battery looking thing on the SNASM2 card) - it won't even start up without one.
I didn't make the kit - it's an official one by Cross Products (a dev hardware company) made in 1992 - based off the SNASM2 tools.