galaxian/galaxian.cpp: 'bongoa' dip switches are memory mapped

[devinacker]

Compared to the parent set, bongoa ignores the AY input ports and reads dip switches from a memory-mapped port.

This set also hacks out the code which initializes the AY port direction bits (compare code at $2288 in both sets), which means the 'noise enable' bits are never initialized either, leaving the noise generator enabled on all three channels. Is that actually what's supposed to happen or should the noise output be disabled by default instead?

[cuavas]

@clawgrip can you please consider this? Did this Bongo set have any PCB mods?

[clawgrip]

Cannot tell... The PCB was modified on many ways.

[jackson2k2]

I don't have access to the ROMset that didn't land in 0.265 (with the correct ROM 5) right now, but there is no AY-3-8910 on there. This is probably a bootleg hack especially considering the '86 date, does it write to standard Moon Cresta sound ports? Set it up like this:

template <bool AY8910>
void galaxian_state::bongo_map(address_map &map)
{
	if (AY8910)
	{
		mooncrst_map_base(map); // no discrete sound
		map(0xb800, 0xb800).mirror(0x7ff).nopw(); // written once at start
	}
	else
	{
		mooncrst_map(map);
	}
	map(0x0000, 0x5fff).rom().region("maincpu", 0); // extend ROM
	map(0xb000, 0xb000).mirror(0x7f8).nopw(); // interrupt enable moved
	map(0xb001, 0xb001).mirror(0x7f8).w(FUNC(galaxian_state::irq_enable_w));
}

void galaxian_state::bongoa(machine_config &config)
{
	mooncrst(config);

	m_maincpu->set_addrmap(AS_PROGRAM, &galaxian_state::bongo_map<false>);
}

Side note: currently the driver needs to be lit on fire, even trying to rewrite the driver I shelved off the work for a year because trying to nail everything down with a hammer and modularize the components is annoying.

EDIT: Also realized that this is not a Moon Cresta board, it's actually a Galaxian board from Namco, so the wiremods are to be expected. R34 is 15K here like Moon Cresta, though. The 5.1K value might actually be a change for Midway boards only. Right now I'd prefer to use mooncrst(config)...

EDIT: Andy confirmed that Namco boards use 15k according to the Japanese schematics. When I finish converting the discrete audio to netlist I'll set out the sound organization straight...

[devinacker]

I don't have the redumped ROM 5 either, but that's also where all the sound-related AY8910 code lives in the original set, so there's a good chance that's what the actual difference is in this set.

[jackson2k2]

For what it's worth, a video of this set has surfaced 3 years back in Japan and this is what the it may apparently should look like: The palette looks different: same as 'bongo', but the main character is green, and Bongo and the monsters are blue! Is there any PROM that matches? https://www.youtube.com/watch?v=ANLFKoMLPRI

[clawgrip]

Hi! If colors are wrong, it's not a matter of changing the PROM, but decoding it properly, as we dumped the PROM from the actual PCB.

Thx.

---

De: 2k2 @.> Enviado: lunes, 6 de mayo de 2024 12:36 Para: mamedev/mame @.> Cc: ClawGrip @.>; Mention @.> Asunto: Re: [mamedev/mame] galaxian/galaxian.cpp: 'bongoa' dip switches are memory mapped (PR #12314)

For what it's worth, a board of this set actually exists and this is what the it may apparently should look like: The palette looks different: same as 'bongo', but the main character is green, and Bongo and the monsters are blue! Is there any PROM that matches? https://www.youtube.com/watch?v=ANLFKoMLPRI

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[jackson2k2]

There's no wiremods around the PROM and the resistors are standard so that leaves out the question unless this board happened to lack such modification... Note that the Jetsoft copyright also still exists in the video, maybe this is a legitimate conversion kit from Jetsoft which wouldn't surprise me.