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drhelius / Gearsystem

Sega Master System / Game Gear / SG-1000 emulator for macOS, Windows, Linux, BSD and RetroArch.
https://x.com/drhelius
GNU General Public License v3.0
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SG-1000 SN76489 PSG chip noise generation #100

Closed siriokds closed 2 months ago

siriokds commented 3 months ago

Hi, SMS (1 and 2), Genesis and Game Gear have and integrated PSG and, in the noise channel implementation, the tapped bits are bits 0 and 3 ($0009), fed back into bit 15.

For the SG-1000, Othello Multivision, SC-3000(H) and Colecovision, the tapped bits are bits 0 and 1 ($0003), fed back into bit 14.

drhelius commented 2 months ago

This is an easy fix. Thanks for reporting!