But the screen wasn't painting the reels and seemed to be stuck in a loop. After much tracing, I finally found that the Timer 1 interrupt at 0x001b stopped firing. Without this interrupt, the game would basically sit in an endless loop waiting for the timer bit to update.
It turns out that the split timer code in the i8051 core needed a small tweak. Once the code was fixed, the reel stops showed up in the operator screen, and the game started accepting coins.
Now that I could see the slot games play properly, I found that PS0716 was not "Quarter Mania", but rather "River Gambler".
With the video slots working, I added support for 5 new romsets to the driver:
- (PS0014) Super Joker Slots
- (PS0022) Red White & Blue Slots
- (PS0043) Double Diamond Slots
- (PS0045) Red White & Blue Slots
- (PS0308) Double Jackpot Slots