SpritesMind.Net

Microchip still sells serial eeproms. I had a quick look at the datasheet of the 24C01 and it seems to operate very similarly to a newer 24xx01 - you may be able to use that. http://www.microchip.com/pagehandler/en-us/products/memory/serialEEPROM/home.html EDIT: Better yet, they still sell 24C01's: ...

The component side of the cart is usually B1 to B32, not A1 to A32. Clearly those are not A1 to A32 as labelled because A1, A2, A31 & A32 are supposed to be power pins.

Thanks for bringing this info Chilly Willy. I have already hard-coded a small Z80 program in my VHDL code to initialize the Z80 stack and enable/disable the FM based on joypad input. I will try to init RAM location $C000 and see how that goes. -- Array containing ROM of db PBCFM init code --;*******...

I've discovered that the #RESET signal on cartridge port pin B27 is stuck to GND in Master System compatibility mode. When in Genesis mode, this pin sends an active-low reset pulse to the cartridge port when the Reset pushbutton is pressed. Therefore, you can't rely on B27 for reset when in Master S...

Thanks for the info Tiido, at least now I know that it can work!

That's actually a very good theory. I'm going to compare the databus values of all my Genesis models with a logic analyzer (as soon as I get my hands on one) during YM2413 and will post the results.

Correction:

The nIORQ signal is in fact present on the Model 2 Genesis, I have confirmed this by finally finding the time to put one under the oscilloscope this evening.

Hmmm, this has me baffled at bit. Why would the YM2413 detection work on a model 1 but not a model 2?

Oh great, that's good to know. And I suppose if you make such a card you can test the prototype out first on a version 2 machine to be sure. :) I wonder if 512K is the limit, or if the version 2 BIOS could even do 1MB at 500000+. I can confirm a 512KB Backup RAM Cart works on: Sega CD Model 1 Bios ...

I remember reading somewhere, and I've searched for it for about an hour before posting but sadly I didn't bookmark it and can't seem to find it, about a trick that was used for console programming to visually determine how much "time" was left before the next VBLANK interrupt. I don't recall if it ...

I want to try and compare the audio quality between this and a 100% VHDL solution.

I can get the YM2413 chips from eBay but I'm a bit weary of relying on said stock; I'd rather have a soft solution.

Here's an interesting discovery:

nIORQ is not present on A19 on the model 2 Genesis. I wonder what else has been removed from the model 2 which we're not aware of yet...

I'm going to experiment with those in the next few days. Clearly A21 and A22 are inputs...

When the Genesis is used in Master System mode (à la Power Base Converter), some of the Genesis signals are converted into signals which were once present on the Master System Cartridge port. I've already found (through the internet and through testing) the following: Genesis -> Master System Mode A...

Here's my first prototype for an FM enabled Power Base Converter. I had the idea to make this after seeing etim's FM sound expansion module for the SMS - why not have the ability to hear FM sound for a SMS game on Megadrive/Genesis as well? To sum up the design, here are the major components: -YM241...