Thanks, I appreciate the support. I do want the money to come in though, so these developments will start to pay for itself again. Of course, I haven't actually sold anything for a while. MIDINES used the squeedo-rev2 PCB, so I made a bit of money off that over a period of several years (about $1 each). Then I gave him the PCB layout so he could make changes or do whatever, it had a good run. So that has been my only 'release' since the first Garage Cart. Eventually I'll have to quit refining and improving stuff and come up with a release, to get things rolling again.
Memblers wrote:I'm still very impressed with the mapper I've come up with using a $1.50 in parts - it supersedes the MMC1 and MMC2.
Sounds interesting! Care to share more? =)
It is evolved from what I mentioned here:
http://nesdev.com/bbs/viewtopic.php?t=6590&start=15
I'll make a real thread about it once I get the prototypes. I'm real picky about the routing and part placement, as usual, heh. It's maybe about the size of a UNROM board, but has 7 chips - all on the same side of the board.
But the IRQ feature is based on the PPU address. You use certain tiles to change the PPU banks between a fixed location, and the value in the bank register(s). I'm not even sure yet what kind of stuff can be done with this. Could do easy text boxes, for one thing. This can also trigger a CPU IRQ at the same time.
There are 2 bank regs for PRG, and 2 bank regs for CHR. The best general-purpose setup I've come up with uses 16kB PRG banks and 2kB CHR banks, but the bank sizes can be adjusted (trade off a feature), only easily by reprogramming here at the 'factory' though. Mirroring control is H/V, and 1-screen H/V.
I also had an idea for an experimental 4-screen mode, that also allows nametable bankswitching. That won't be in the 'default' build (uses jumpers), but may be available, if wanted. Another feature of the mapper that isn't as interesting by itself, is that it enables an addressable parallel port to the NES expansion port. That could be fun later.