I decided it's about time to order some hardware and build a test cartridge. For the connecotrs I've found two options: Standard and Tall headers. The standard height would just plug into the GPIO port, but the tall would stick out of the back of the cart, allowing other things to be connected to GPIO at the same time. I like the idea of having a joystick cart that has connectors for things like Commodore or even NES joysticks. That would plug in first, then the game would plug in on top of that. Could get quite crazy looking, but may of the older consoles had tons of hardware that could be plugged in all over. For now, I'll order the standard height so I can get started on a test cart. For the memory chip, I'll be ordering a few of the 4Mbit EEPROM chips. I'll need 1 of them for a single chip cart, and at least 2 for a multi-chip cart. I already have a small stash of protoboard large enough to mount the headers and build a simple board. I just need to see if there is any supporting hardware I need for the EPPROM chips. Accodring to this page, it should be a very simple matter of connectng some wires and running the code. If that's the case(will confirm this connection method is proper for long term use), then these low capacity carts will be very simple. Just a single IC, connected to some of the pins on the header. Seems like a waste of space and hardware, but that can be handled later. I plan to make the carts fairly large to leave room for more advanced carts in the future. I can easily hand wire some test carts when the hardware arrives, so this should be just fine for testing. 

On a random note, I found a nice looking EEPROM program written in python. I was thinking of how I can make a program that will handle reading of the EEPROM, but no need. I could have this program load on start up, and have it load the EEPROM data into another program. EEPROM-PiPython.

Pricing

EEPROMs, with shipping: $15.31 USD

Headers, free shipping: $8.18 USD

Total: $23.49 USD

Price per cart: $3.26 USD

The price per cart is my cost, not including the solder, wires, and PCBs, all of which I have already. A fab house can likely make these far cheaper and faster than I can, so I'll be designing and ordering some premade boards when I finalize a few designs. There is much to consider, such as physical size, memory type and layout, pin assignments, and even board color. 

I accomplished what I set out to do with this log, so I'll move onto the next thing.