I’m looking for an adaptor/ROM emulator with a 32K SRAM, which emulates a 32K ROM for the CoCo, that could be written to from one of my PC’s USB ports. If you know of something that would hook up to a parallel port, I could probably find a way to use that. This would give a quick and easy means for trying out ROM images, developing new software, etc., and doing it with a real CoCo. I have seen them for Atari development systems, and I think I’ve seen them for the Turbo Grafx-16. I’m surprised that I can’t find one for the CoCo. I’ve looked in Cloud9, and I think I remember seeing a cartridge that allows you to try out EPROMs, though I didn’t see it this time when I looked. That is a relatively slow way to do it anyway, though, because it requires erasing the EPROM (3-5 minutes) before you can reprogram it(another 5 minutes?). One could get around a little of this delay by having several 27256’s, but there is a limit to the erasures allowed on each device. The SRAM masquerading as a ROM eliminates all of these limitations, making it faster, easier and cheaper to develope a cartridge based game or application. Does anyone know where I can find such a thing?
This is an URL to a picture of a board that does what I want (I think), only it’s for an Atari 7800: Atari 7800 development board
This is a schematic for the same board: Atari 7800 development board schematic
This board appears to use the 7800 to fetch the intended contents for the 5 32K SRAM’s, and it’s using a parallel interface to the PC. That’s not exactly what I’m looking for, but if a parallel to this for the CoCo is all that is readily available… well, I could probably live with it. 
Thanks,
HH
I’ve seen many ROM emulators on the web and most are expensive. Remember, you also have the “free” option of just emulating the ROM on the PC using one of the CoCo emulators.
My Rainbow IDE makes CoCo development hardware-free in most cases by letting you build the ROM image by clicking a few options on the sidebar and clicking GO. The M.E.S.S. emulator window will pop up with the CoCo ROM running. There really is no better way to design and test CoCo ROMs, in my opinion.
The IDE approach works for most, but not all, ROM projects. Obviously, any ROM that uses hardware that’s only available on the real CoCo will have to be tested on the real CoCo.
This is where the CoCoNet project fits in. CoCoNet will let you boot the CoCo up using the wireless pak or ROM-only/bitbanger pak to start up with any ROM that’s mounted on the PC side. This includes Disk BASIC, 8K/16K games, other DOS ROMs, etc. As long as the ROM can run in all-RAM mode on the CoCo, the CoCo shouldn’t notice any difference.
The ideal method is to use the wireless pak which talks to the applet on the PC via bluetooth. The CoCo then emulates a floppy drive system, virtual ROM paks, and internet connection.
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