Understood and hooked up sound HW in Little Robin, that is a weird combination of 2 DAC sound chips, the video scanline register, interrupt generation (irq lv 4 with an input port that defines the kind of irq, currently hooked up with the video frame number) and two lovely 16-bit port registers (one for each DAC) that alternates the resulting 8-bit sound index according to an external source (frame number % 16 with current implementation, as each “sound irq” happens every 8 frames). And by alternation it means in the sense of muxing between LSB or MSB of the aforementioned sound index (that is obviously pointless if isn’t a form of protection).

It’s no secret that the team is currently doing major efforts in emulating PC-AT based HW. Grull Osgo in particular is working on California Chase, that is currently more or less working with a “MS-DOS” kludge (you need to type boot after that Win 98 fails to boot). I’ve tweaked the code a little and added an idle skip for it.

Street Games 2 recently started working after some tweaks to the VGA code:

EDIT: added sound to Cali Chase -> https://mamedev.emulab.it/kale/wp-content/uploads/2012/02/cali3.mp3

Another long standing bug fixed, this time with Joyful Road / Munch Mobile substained sounds.

Lord Nightmare did some studying of the schematics in there, and ended up with a bunch of unemulated ports that directly goes to the AY reset lines. Hooking that up makes the sound in this one to finally work.

Investigated with Phil Bennett and Charles MacDonald about why Bonanza Bros. never ever played samples from when it was marked as working. It turned out that Sega System 24 HW uses a FRC that also does a previously unemulated IRQ service.

Implemented ES5510 DSP DRAM latches to Taito F3 driver, this adds full sound to Riding Fight and gives correct sound to Ring Rage without going into test mode first.