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phoboz / fpgagen

SEGA Genesis/Megadrive FPGA core
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Megadrive 1/2 mode switch #12

Closed jotego closed 7 years ago

jotego commented 7 years ago

Hi,

The Megadrive model 1 used the YM2612 but the model 2 used YM3438. It looks like one audible difference was the lack of volume limiter in the accumulator unit of YM3438, according to the application notes.

I have implemented an YM3438 mode into JT12. I need one OSD switch to select Megadrive model. The difference is extremely noticeable in the "ring" sound of Sonic.

Thank you, Pepe

robinsonb5 commented 7 years ago

Done - the dipswitches signal is now 16 bits wide rather than 12. Bit 5 is mapped to the model 2 select (which is now a menu item). Since this is so closely related to the channel mute idea, I've done that too, and bits 6-12 are now toggled by keys 1 - 7 (above qwerty, not keypad).

jotego commented 7 years ago

Thank you!

El El dom, 5 mar 2017 a las 15:42, robinsonb5 notifications@github.com escribió:

Done - the dipswitches signal is now 16 bits wide rather than 12. Bit 5 is mapped to the model 2 select (which is now a menu item). Since this is so closely related to the channel mute idea, I've done that too, and bits 6-12 are now toggled by keys 1 - 7 (above qwerty, not keypad).

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