I have started to look at implementing MSU-1 support to your SNES core:http://helmet.kafuka.org/msu1.htm
So far I have setup some code in verilator (SystemVerilog), and begun adding functionality to handle the MSU_ID, MSU_STATUS and MSU_TRACK registers for both read and write. I have also started to add the code into a fork or your repository (I will make this public soon). I thought I would reach out to you now to ask a few questions before I proceed much further:
1) Are you planning or are currently working on MSU-1 support? If so, I can help, or leave you to it!
Up to you!
2) If I was to add in support, I notice you have a src/chip folder containing the additional special chip implementations, along with a mapper pattern to select these chips onto the bus... I have created another chip folder (src/chip/MSU) and started to add a MSU map. Would this be your preferred method for adding in MSU functionality? Even considering it is not a real special chip?
3) Are you okay with me adding further SV to your project? Given that the majority of your code is VHDL?