Rap It Up

Hello friends! We’re back with the Daily Devlog! This one’s a quickie because the docs were (mostly) clear and I was listening to Rob Apollo while working. Let’s dive right in so I can run a mile on 5.5 hours of sleep rather than only 5!

The Final Boss of MBCs

When I started to do MBCs, the scope of this project was to do no MBC, MBC1, MBC2, MBC3, and maybe MBC5. I have been completing them largely in sequence:

• MBC1
• MBC2
• No MBC
• MBC3 (yesterday)

This leaves only MBC5, today’s feature. I thought MBC5 was going to be difficult, but it was probably the easiest MBC besides no MBC, which isn’t even an MBC!

MBC5 is basically a simpler and bigger version of MBC1, with two exceptions:

• Rumble:
  Apparently, cartridges can shake it down because some MBC5 variants have a rumble motor controlled by bit 3 of the CRAM selector. If there is rumble, that bit is dead.

• Chunks
  Every other MBC I’ve implemented followed this general rule: the ROM is exposed of 0x8000 bytes. Those bytes are split into four sections, each of 0x2000 bytes. Depending on which register you wrote to, it would be a different MBC command/