A few noob questions and hardware hacking

Hello,

I haven't been able to find a whole lot of documentation on NESmaker, so I haven't purchased it yet. I had a few questions.

NESmaker states that no programming is required. However, if I want to embed assembly code, can I? How is it typically embedded? I've done a lot of 6502 back in the day, so I found this possibility exciting to me.

I'm also an embedded hardware guy and thought it might be fun to add some additional I/O through the cart port for a few fun connectivity ideas I had. I was wondering if there were any open hardware projects out there (kicad or eagle) for an NES game cart so I don't have to reinvent the wheel?

You can tie 6502 assembly "scripts" you write to certain events like pressing A from the UI, but you can also just edit the code directly.

Full source code for the engine is available, and you can browse it without actually buying the software if you'd like to take a look to see how much you understand: http://www.thenew8bitheroes.com/

Download, unzip, and it's in the GameEngineData folder.

I don't have an answer for the hardware question. Certain flash carts allow one to write custom mappers for the FGPA in verilog if that's not too high level. Here are some resources for the powerpak: https://wiki.nesdev.com/w/index.php/PowerPak#PowerPak_development_resources

Thank you Kasumi, that was actually a big help. I also took the plunge and purchased a license after being very impressed by the multiple projects undertaken by the community.

The assembly was easy to understand. Still trying to seek the EQU's for some of the addresses, but mainly for curiosity sake.

On the hardware side, although it may sound ambitious, this is what i was thinking of doing:

I would like to create a cart that contains typical flash memory for CPU and PPU, with special addresses for I/O. In particular, a pair of memory addresses that would facilitate communication to an onboard processor to connect it to a network, such as WiFi. I have done similar things on other retro hardware, but the NES would be the apex.

A WiFi connected Nintendo embedded in the cart would be hilarious. While it would make online multiplayer possible, I have other fun goals.

There are certainly no shortage of schematics out there, but before i layout a board, i just wanted to make sure a) i looked at the right schematic b) i'm not re-inventing anything.

Since I own an open hardware company, whatever I do will be open source.