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lgtnfght: removed NMI connection as it does not exist on schematics. #13819

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Merged
merged 1 commit into from
Jun 14, 2025

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jotego
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@jotego jotego commented Jun 13, 2025

Trigon schematics show a pull-up resistor at the NMI pin. However, the driver connects that signal.

image

This PR removes the connection in the driver. The sound is not affected after the change.

I created a separate branch in my fork for this, so feel free to push other changes to it.

@cuavas
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cuavas commented Jun 14, 2025

Just as a sanity check, have you checked continuity on a real board to ensure it isn’t an error in the schematic? It could have a pullup resistor as well as a connection if it’s being driven from an open collector output, for example.

@happppp
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happppp commented Jun 14, 2025

No NMI routine at 0x66 in the Z80 ROM.
If the hw did have NMI hooked up and not used it, I'd expect at least a retn safety measure like some of the other games in this driver.

@happppp happppp changed the title removed NMI connection as it does not exist on schematics. lgtnfght: removed NMI connection as it does not exist on schematics. Jun 14, 2025
@ajrhacker ajrhacker merged commit c166eb1 into mamedev:master Jun 14, 2025
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4 participants