Bharathi’s Status Report for 4/19/25

Accomplished

  • Debugged DMG Acid Test — frame rendered appears to be fully correct. Also fixed the missing hand issue on Dr.Mario in simulation.
  • Debugged Tetris and Dr.Mario on VGA with team. Tetris looks mostly functional but the game appears to run 2x faster. Dr.Mario is stuck after the pill is spawned & before it is thrown.
  • Fixed synthesis issues related to the Audio Test. Technically we have all the pieces for the APU but integrating it is likely to introduce a number of other issues so I have postponed it until we get Dr.Mario and Tetris working perfectly.
  • Ruslana and I spent a lot of time investigating the Dr Mario pill issue on simulation. Unfortunately, the bug happens after such a long time that looking at in simulation is not the most productive way to attacking the problem. However, simulation allowed us to get more specific areas / registers / addresses to look at.

Schedule / Progress

We are somewhat behind schedule given the APU status but otherwise integration is going pretty well.

Next Step(s)

  • Finish debugging Dr.Mario and Tetris.
  • Potentially integrate APU.

Tools/knowledge:

  • We need to learn the GameBoy spec thoroughly to implement it correctly. The largest challenge with this was trying to parse the many informal / unofficial documentation (that was usually contradictory).
  • I also learnt a lot related to Intel / Altera tooling and designing specifically for FPGAs. Prior to this, most of my hardware experience had been on simulation.
  • Implementing the PPU from scratch also forced me to explore more new and complex strategies to testbench my code (both separately and after integration).
  • I also got plenty of practice using wave viewers and software debuggers during debugging.

Leave a Reply

Your email address will not be published. Required fields are marked *